Publications by authors named "Saadullah Khan"

40 Publications

Novel Homozygous Mutations in the Genes , , and in Four Families Underlying Congenital Ichthyosis.

Genes (Basel) 2021 Mar 5;12(3). Epub 2021 Mar 5.

Department of Biotechnology and Genetic Engineering, Kohat University of Science & Technology (KUST), Kohat 26000, Khyber Pakhtunkhwa, Pakistan.

Background: Ichthyoses are a large group of hereditary cornification disorders, which are both clinically and etiologically heterogeneous and affect mostly all the skin surface of the patients. Ichthyosis has its origin in an ancient Greek word "ichthys" meaning fish, this is because the ichthyosis patients have dry, thickened, and scaly skin. There is an excess accumulation of epidermal cells resulting in the appearance of continuous and widespread scales on the body. There are many varieties of ichthyosis with a broad spectrum of intensity, severity, and associated symptoms, most of them are extremely rare. Ichthyosis vulgaris is the most frequently occurring type of ichthyoses.

Method: The present study consists of four Pakistani ichthyosis families (A, B, C, and D). Whole exome sequencing (WES) approach was used to identify the pathogenic sequence variants in probands. The segregation of these variants in other participants was confirmed by Sanger sequencing.

Results: Total four variants including, two splice site (: c.2088 + 1G > A) and (: c.882 + 1G > T), a missense (: c.419C > T; p. Ala140Val), and a nonsense (: c.6109C > T; p. Arg2037Ter) variant were identified in families A, C, B, and D, respectively, as causative mutations responsible for ichthyosis in these families.

Conclusion: Our study unravels the molecular etiology of the four Pakistani ichthyosis families and validates the involvement of and , in the etiology of different forms of ichthyosis. In addition, this study also aims to give a detailed clinical report of the studied ichthyosis families.
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http://dx.doi.org/10.3390/genes12030373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7999895PMC
March 2021

Genetic Spectrum of Syndromic and Non-Syndromic Hearing Loss in Pakistani Families.

Genes (Basel) 2020 Nov 11;11(11). Epub 2020 Nov 11.

Institute of Human Genetics, Julius Maximilians University Würzburg, 97074 Würzburg, Germany.

The current molecular genetic diagnostic rates for hereditary hearing loss (HL) vary considerably according to the population background. Pakistan and other countries with high rates of consanguineous marriages have served as a unique resource for studying rare and novel forms of recessive HL. A combined exome sequencing, bioinformatics analysis, and gene mapping approach for 21 consanguineous Pakistani families revealed 13 pathogenic or likely pathogenic variants in the genes , , , , , , and , with an overall resolve rate of 61.9%. and were the most frequently involved genes in this cohort. All the identified variants were either homozygous or compound heterozygous, with two of them not previously described in the literature (15.4%). Overall, seven missense variants (53.8%), three nonsense variants (23.1%), two frameshift variants (15.4%), and one splice-site variant (7.7%) were observed. Syndromic HL was identified in five (23.8%) of the 21 families studied. This study reflects the extreme genetic heterogeneity observed in HL and expands the spectrum of variants in deafness-associated genes.
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http://dx.doi.org/10.3390/genes11111329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7709052PMC
November 2020

Homozygous variants of EDAR underlying hypohidrotic ectodermal dysplasia in three consanguineous families.

Eur J Dermatol 2020 Aug;30(4):408-416

Department of Biochemistry, Hazara University, Mansehra, Khyber Pakhtunkhwa, Pakistan.

Background: Hypohidrotic ectodermal dysplasia (HED) is a congenital anomaly characterized by hypohydrosis, hypotrichosis and hypodontia. Mutations in at least four genes (EDAR, EDARADD, WNT10A, TRAF6) have been reported to cause both autosomal recessive and autosomal dominant forms of HED. Mutations in two other genes (EDA and IKBKG) have been reported to cause X-linked HED.

Objectives: To clinically characterize three consanguineous families (A-C) segregating with autosomal recessive HED and identify possible disease-causing variants of EDAR and EDARADD genes.

Materials And Methods: The genes, EDAR and EDARADD, were sequenced in Family A and C, and exome sequencing was performed in Family B. Additionally, in Family A and C, the effect of the identified variants was examined by analysis of EDAR mRNA, extracted from hair follicles from both affected and unaffected members.

Results: Sequence analysis revealed three possible disease-causing EDAR variants including a novel splice acceptor site variant (IVS3-1G > A) in Family A and two previously reported mutations (p.[Ala26Val], p.[Arg25*]) in the two other families. Previously, the nonsense variant p.(Arg25*) was reported only in the heterozygous state. Analysis of the RNA, extracted from hair follicles, revealed skipping of a downstream exon in EDAR and complete degradation of EDAR mRNA in affected members in family A and C, respectively. Computational modelling validated the pathogenic effect of the two variants identified in Family B and C.

Conclusion: The three variants reported here expand the spectrum of EDAR mutations associated with HED which may further facilitate genetic counselling of families segregating with similar disorders in the Pakistani population.
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http://dx.doi.org/10.1684/ejd.2020.3844DOI Listing
August 2020

A novel nonsense variant in SLC24A4 causing a rare form of amelogenesis imperfecta in a Pakistani family.

BMC Med Genet 2020 05 7;21(1):97. Epub 2020 May 7.

Institute of Molecular Biology and Biotechnology (IMBB), Center for Research in Molecular Medicine (CRiMM), The University of Lahore, Lahore, Pakistan.

Background: Amelogenesis imperfecta (AI) is a highly heterogeneous group of hereditary developmental abnormalities which mainly affects the dental enamel during tooth development in terms of its thickness, structure, and composition. It appears both in syndromic as well as non-syndromic forms. In the affected individuals, the enamel is usually thin, soft, rough, brittle, pitted, chipped, and abraded, having reduced functional ability and aesthetics. It leads to severe complications in the patient, like early tooth loss, severe discomfort, pain, dental caries, chewing difficulties, and discoloration of teeth from yellow to yellowish-brown or creamy type. The study aimed to identify the disease-causing variant in a consanguineous family.

Methods: We recruited a consanguineous Pashtun family of Pakistani origin. Exome sequencing analysis was followed by Sanger sequencing to identify the pathogenic variant in this family.

Results: Clinical analysis revealed hypomaturation AI having generalized yellow-brown or creamy type of discoloration in affected members. We identified a novel nonsense sequence variant c.1192C > T (p.Gln398*) in exon-12 of SLC24A4 by using exome sequencing. Later, its co-segregation within the family was confirmed by Sanger sequencing. The human gene mutation database (HGMD, 2019) has a record of five pathogenic variants in SLC24A4, causing AI phenotype.

Conclusion: This nonsense sequence variant c.1192C > T (p.Gln398*) is the sixth disease-causing variant in SLC24A4, which extends its mutation spectrum and confirms the role of this gene in the morphogenesis of human tooth enamel. The identified variant highlights the critical role of SLC24A4 in causing a rare AI type in humans.
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http://dx.doi.org/10.1186/s12881-020-01038-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7206816PMC
May 2020

Association of sequence variants in frizzled-6 with autosomal recessive nail dysplasia (NDNC-10) in Pashtun families.

J Pak Med Assoc 2020 Jan;70(1):143-146

Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, Khyber Pakhtunkhwa, Pakistan.

Primitive epidermis develops the nail apparatus. Nails have a strong and inflexible nail plate at the end of each digit. Very few genes responsible for causing nonsyndromic form of nail dysplasia have been reported. In the current study, peripheral blood samples were collectedfrom three unaffected individuals and four affectedindividuals of Family A, while blood from two affected and three unaffected individuals were taken of Family B. Genotyping in both the families was performed using highly polymorphic short tandem repeat microsatellite markers. Sanger sequence of the FZD6 gene was performed and analysed for segregation analysis. A comparative modelling approach was used to predict the three-dimensional structures of FZD-6 protein using Modeller 4. Linkage analysis mapped a disease locus on chromosome 8q22.3, harbouring FZD6. Targeted Sanger sequencing of all the coding exons of FZD6 revealed a nonsense sequence variant in pedigree A, whereas a missense sequence variant in pedigree B. Finding and literature indicates the disease spectrum of Pakistani population with claw-shaped nail dysplasia, particularly in families of Pashtun origin.
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http://dx.doi.org/10.5455/JPMA.9200DOI Listing
January 2020

Genetic study of Khyber-Pukhtunkhwa resident Pakistani families presenting primary microcephaly with intellectual disability.

J Pak Med Assoc 2019 Dec;69(12):1812-1816

Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Khyber Pakhtunkhwa, Pakistan.

Objective: To investigate the genetic factor responsible for causing microcephaly and determine allelic heterogeneity of Abnormal spindle microtubule gene.

Methods: The genetic study was conducted at the Kohat University of Science and Technology, Kohat, and Gomal University, D.I.Khan, Pakistan, during 2017-18, and comprised 5 consanguineous families from South Waziristan, Kurram Agency, Karak, Bannu and Dera Ismail Khan regions of the country's Khyber Pakhtukhwa province. Blood samples from all available and cooperative family members (including normal and affected) were obtained, and molecular analysis was carried out through whole genome single nucleotide polymorphisms genotyping, exome sequencing and Sanger sequencing.

Results: Of the 15 patients, 9(60%) were males and 6(40%) were females. Genetic mapping revealed linkage to the MCPH5 locus which harbours the microcephaly-associated abnormal spindle-like microcephaly gene. Mutation analysis of the gene identified missense mutation c.3978G>A (p.Trp1326*) in families A, B and C, a deletion mutation c.7782_7783delGA (p.(Lys2595Serfs*6)) in family D, and a splice site defect c.2936+5G>A in family E.

Conclusions: There was suggestion of strong founder effect of mutation c.3978G>A (p.Trp1326*).
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http://dx.doi.org/10.5455/JPMA.300681DOI Listing
December 2019

Deleterious Variants in , and Causing Isolated and Syndromic Tooth Agenesis: A Structural Perspective from Molecular Dynamics Simulations.

Int J Mol Sci 2019 Oct 24;20(21). Epub 2019 Oct 24.

Institute of Molecular Biology and Biotechnology (IMBB), Center for Research in Molecular Medicine (CRiMM), The University of Lahore, Lahore 54000, Pakistan.

The dental abnormalities are the typical features of many ectodermal dysplasias along with congenital malformations of nails, skin, hair, and sweat glands. However, several reports of non-syndromic/isolated tooth agenesis have also been found in the literature. The characteristic features of hypohidrotic ectodermal dysplasia (HED) comprise of hypodontia/oligodontia, along with hypohidrosis/anhidrosis, and hypotrichosis. Pathogenic variants in , , , and , cause the phenotypic expression of HED. Genetic alterations in and cause particularly non-syndromic/isolated oligodontia. In the current project, we recruited 57 patients of 17 genetic pedigrees (A-Q) from different geographic regions of the world, including Pakistan, Egypt, Saudi Arabia, and Syria. The molecular investigation of different syndromic and non-syndromic dental conditions, including hypodontia, oligodontia, generalized odontodysplasia, and dental crowding was carried out by using exome and Sanger sequencing. We have identified a novel missense variant (c.311G>A; p.Arg104His) in in three oligodontia patients of family A, two novel sequence variants (c.207delinsTT, p.Gly70Trpfs*25 and c.1300T>G; p.Try434Gly) in in three patients of family B and four patients of family C, respectively. To better understand the structural and functional consequences of missense variants in WNT10A and EDAR on the stability of the proteins, we have performed extensive molecular dynamic (MD) simulations. We have also identified three previously reported pathogenic variants (c.1076T>C; p.Met359Thr), (c.1133C>T; p.Thr378Met) and (c.594_595insC; Gly201Argfs*39) in in family D (four patients), E (two patients) and F (one patient), correspondingly. Presently, our data explain the genetic cause of 18 syndromic and non-syndromic tooth agenesis patients in six autosomal recessive and X-linked pedigrees (A-F), which expand the mutational spectrum of these unique clinical manifestations.
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http://dx.doi.org/10.3390/ijms20215282DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6862269PMC
October 2019

A novel pathogenic missense variant in CNNM4 underlying Jalili syndrome: Insights from molecular dynamics simulations.

Mol Genet Genomic Med 2019 09 25;7(9):e902. Epub 2019 Jul 25.

Institute of Molecular Biology and Biotechnology (IMBB), Centre for Research in Molecular Medicine (CRiMM), The University of Lahore, Lahore, Pakistan.

Background: Jalili syndrome (JS) is a rare cone-rod dystrophy (CRD) associated with amelogenesis imperfecta (AI). The first clinical presentation of JS patients was published in 1988 by Jalili and Smith. Pathogenic mutations in the Cyclin and CBS Domain Divalent Metal Cation Transport Mediator 4 (CNNM4) magnesium transporter protein have been reported as the leading cause of this anomaly.

Methods: In the present study, a clinical and genetic investigation was performed in a consanguineous family of Pakistani origin, showing characteristic features of JS. Sanger sequencing was successfully used to identify the causative variant in CNNM4. Molecular dynamics (MD) simulations were performed to study the effect of amino acid change over CNNM4 protein.

Results: Sequence analysis of CNNM4 revealed a novel missense variant (c.1220G>T, p.Arg407Leu) in exon-1 encoding cystathionine-β-synthase (CBS) domain. To comprehend the mutational consequences in the structure, the mutant p.Arg407Leu was modeled together with a previously reported variant (c.1484C>T, p.Thr495Ile) in the same domain. Additionally, docking analysis deciphered the binding mode of the adenosine triphosphate (ATP) cofactor. Furthermore, 60ns MD simulations were carried out on wild type (p.Arg407/p.Thr495) and mutants (p.Arg407Leu/p.Thr495Ile) to understand the structural and energetic changes in protein structure and its dynamic behavior. An evident conformational shift of ATP in the binding site was observed in simulated mutants disrupting the native ATP-binding mode.

Conclusion: The novel identified variant in CNNM4 is the first report from the Pakistani population. Overall, the study is valuable and may give a novel insight into metal transport in visual function and biomineralization.
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http://dx.doi.org/10.1002/mgg3.902DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6732295PMC
September 2019

Biallelic mutations in the LPAR6 gene causing autosomal recessive wooly hair/hypotrichosis phenotype in five Pakistani families.

Int J Dermatol 2019 Aug 11;58(8):946-952. Epub 2019 May 11.

Institute of Biochemistry, University of Balochistan, Quetta, Pakistan.

Background: Autosomal recessive wooly hair/hypotrichosis is an inherited disorder of hair characterized by less dense, short, and tightly curled hair on the scalp and sometimes less dense to complete absence of eyebrows and eyelashes. Autosomal recessive wooly hair/hypotrichosis phenotypes are mostly associated with pathogenic sequence variants in LIPH and LPAR6 genes.

Methods: To find out the molecular basis of the disease, five families with autosomal recessive wooly hair/hypotrichosis were recruited for genetic analysis. Direct Sanger sequencing of LIPH and LPAR6 genes was carried out using BigDye chain termination chemistry. P2RY5 protein homology models were developed to study the effect of mutation on protein structure in a family having novel mutation.

Results: Sanger sequencing revealed a novel homozygous missense mutation (c.47A>T) in the LPAR6 gene in family A, while recurrent mutation (c.436G>A) was detected in the rest of the four families (B-E). Protein homology models for both native and mutant P2RY5 protein were developed to study the difference in subtle structural features because of Lys16Met (K16M) mutation. We observed that P2RY5 mutation results decrease in the number of ionic interactions detrimental to the protein stability. Protein modeling studies revealed that the novel mutation identified here decreased the number of ionic interactions by affecting physicochemical parameters of the protein, leading to an overall decrease in protein stability with no major secondary structural changes.

Conclusion: The molecular analysis further confirms the frequent involvement of LPAR6 in autosomal recessive wooly hair/hypotrichosis, while the bioinformatic study revealed that the missense mutation destabilizes the overall structure of P2RY5 protein.
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http://dx.doi.org/10.1111/ijd.14480DOI Listing
August 2019

Variants in KIAA0825 underlie autosomal recessive postaxial polydactyly.

Hum Genet 2019 Jun 13;138(6):593-600. Epub 2019 Apr 13.

Department of Molecular and Human Genetics, Center for Statistical Genetics, Baylor College of Medicine, 1 Baylor Plaza 700D, Houston, TX, 77030, USA.

Postaxial polydactyly (PAP) is a common limb malformation that often leads to cosmetic and functional complications. Molecular evaluation of polydactyly can serve as a tool to elucidate genetic and signaling pathways that regulate limb development, specifically, the anterior-posterior specification of the limb. To date, only five genes have been identified for nonsyndromic PAP: FAM92A, GLI1, GLI3, IQCE and ZNF141. In this study, two Pakistani multiplex consanguineous families with autosomal recessive nonsyndromic PAP were clinically and molecularly evaluated. From both pedigrees, a DNA sample from an affected member underwent exome sequencing. In each family, we identified a segregating frameshift (c.591dupA [p.(Q198Tfs*21)]) and nonsense variant (c.2173A > T [p.(K725*)]) in KIAA0825 (also known as C5orf36). Although KIAA0825 encodes a protein of unknown function, it has been demonstrated that its murine ortholog is expressed during limb development. Our data contribute to the establishment of a catalog of genes important in limb patterning, which can aid in diagnosis and obtaining a better understanding of the biology of polydactyly.
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http://dx.doi.org/10.1007/s00439-019-02000-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6724712PMC
June 2019

Genetic studies of multiple consanguineous Pakistani families segregating oculocutaneous albinism identified novel and reported mutations.

Ann Hum Genet 2019 07 13;83(4):278-284. Epub 2019 Mar 13.

Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan.

Oculocutaneous albinism (OCA) is an autosomal-recessive disorder of a defective melanin pathway. The condition is characterized by hypopigmentation of hair, dermis, and ocular tissue. Genetic studies have reported seven nonsyndromic OCA genes, among which Pakistani OCA families mostly segregate TYR and OCA2 gene mutations. Here in the present study, we investigate the genetic factors of eight consanguineous OCA families from Pakistan. Genetic analysis was performed through single-nucleotide polymorphism (SNP) genotyping (for homozygosity mapping), whole exome sequencing (for mutation identification), Sanger sequencing (for validation and segregation analysis), and quantitative PCR (qPCR) (for copy number variant [CNV] validation). Genetic mapping in one family identified a novel homozygous deletion mutation of the entire TYRP1 gene, and a novel deletion of exon 19 in the OCA2 gene in two apparently unrelated families. In three further families, we identified homozygous mutations in TYR (NM_000372.4:c.1424G > A; p.Trp475*), NM_000372.4:c.895C > T; p.Arg299Cys), and SLC45A2 (NM_016180:c.1532C > T; p.Ala511Val). For the remaining two families, G and H, compound heterozygous TYR variants NM_000372.4:c.1037-7T > A, NM_000372.4:c.1255G > A (p.Gly419Arg), and NM_000372.4:c.1255G > A (p.Gly419Arg) and novel variant NM_000372.4:c.248T > G; (p.Val83Gly), respectively, were found. Our study further extends the evidence of TYR and OCA2 as genetic mutation hot spots in Pakistani families. Genetic screening of additional OCA cases may also contribute toward the development of Pakistani specific molecular diagnostic tests, genetic counseling, and personalized healthcare.
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http://dx.doi.org/10.1111/ahg.12307DOI Listing
July 2019

Novel mutations in ALDH1A3 associated with autosomal recessive anophthalmia/microphthalmia, and review of the literature.

BMC Med Genet 2018 09 10;19(1):160. Epub 2018 Sep 10.

Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, Khyber Pakhtunkhwa, 26000, Pakistan.

Background: Autosomal recessive anophthalmia and microphthalmia are rare developmental eye defects occurring during early fetal development. Syndromic and non-syndromic forms of anophthalmia and microphthalmia demonstrate extensive genetic and allelic heterogeneity. To date, disease mutations have been identified in 29 causative genes associated with anophthalmia and microphthalmia, with autosomal dominant, autosomal recessive and X-linked inheritance patterns described. Biallelic ALDH1A3 gene variants are the leading genetic causes of autosomal recessive anophthalmia and microphthalmia in countries with frequent parental consanguinity.

Methods: This study describes genetic investigations in two consanguineous Pakistani families with a total of seven affected individuals with bilateral non-syndromic clinical anophthalmia.

Results: Using whole exome and Sanger sequencing, we identified two novel homozygous ALDH1A3 sequence variants as likely responsible for the condition in each family; missense mutation [NM_000693.3:c.1240G > C, p.Gly414Arg; Chr15:101447332G > C (GRCh37)] in exon 11 (family 1), and, a frameshift mutation [NM_000693.3:c.172dup, p.Glu58Glyfs*5; Chr15:101425544dup (GRCh37)] in exon 2 predicted to result in protein truncation (family 2).

Conclusions: This study expands the molecular spectrum of pathogenic ALDH1A3 variants associated with anophthalmia and microphthalmia, and provides further insight of the key role of the ALDH1A3 in human eye development.
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http://dx.doi.org/10.1186/s12881-018-0678-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6131798PMC
September 2018

Molecular Characterization of β-Thalassemia Mutations Via the Amplification Refractory Mutation System-Polymerase Chain Reaction Method at the North Waziristan Agency, Pakistan.

Hemoglobin 2018 Mar;42(2):91-95

a Department of Biotechnology , University of Science and Technology Bannu (USTB) , Bannu , Khyber Pakhtunkhwa Province , Pakistan.

β-Thalassemia (β-thal) is a monogenic disease characterized by mutations on the HBB gene, affecting the production of globin that results in hypochromic and microcytic anemia. The aim of this study was to determine the prevalence of six common β-thal mutations, and their frequency and inheritance pattern in affected populations of North Waziristan Agency, Pakistan. In this study, 130 blood samples from 37 unrelated β-thalassemic families having a minimum of one transfusion-dependent child with β-thal major (β-TM), were retrieved either from the Thalassaemia Centre for Women and Children Hospital Bannu or their home towns situated in Noth Waziristan Agency. All samples were analyzed by the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) using six allele-specific primers for the presence of the six β-thal mutations common in the Pakistani population. Of the six common mutations, our study demonstrated five HBB mutations comprising HBB: c.27_28insG, HBB: c.92+5G>C, HBB: c.126_129delCTTT, HBB: c.92+1G>T and HBB: c.17_18delCT from the families studied, while mutation HBB: c.47G>A [codon 15 (G>A)] was not detected in any of the studied families. Furthermore, the HBB: c.27_28insG and HBB: c.92+5G>C were noted to be the most common with frequencies of 42.85 and 31.42%, respectively. The findings of the present study may be useful in launching carrier screening and prenatal diagnosis (PND) programs by screening analyzed and other unanalyzed affected families for the possible presence of common mutations through the ARMS-PCR technique that will help to control the disease.
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http://dx.doi.org/10.1080/03630269.2018.1487308DOI Listing
March 2018

Novel candidate genes and variants underlying autosomal recessive neurodevelopmental disorders with intellectual disability.

Hum Genet 2018 Sep 22;137(9):735-752. Epub 2018 Aug 22.

Department of Molecular and Human Genetics, Center for Statistical Genetics, Baylor College of Medicine, 1 Baylor Plaza 700D, Houston, TX, 77030, USA.

Identification of Mendelian genes for neurodevelopmental disorders using exome sequencing to study autosomal recessive (AR) consanguineous pedigrees has been highly successful. To identify causal variants for syndromic and non-syndromic intellectual disability (ID), exome sequencing was performed using DNA samples from 22 consanguineous Pakistani families with ARID, of which 21 have additional phenotypes including microcephaly. To aid in variant identification, homozygosity mapping and linkage analysis were performed. DNA samples from affected family member(s) from every pedigree underwent exome sequencing. Identified rare damaging exome variants were tested for co-segregation with ID using Sanger sequencing. For seven ARID families, variants were identified in genes not previously associated with ID, including: EI24, FXR1 and TET3 for which knockout mouse models have brain defects; and CACNG7 and TRAPPC10 where cell studies suggest roles in important neural pathways. For two families, the novel ARID genes CARNMT1 and GARNL3 lie within previously reported ID microdeletion regions. We also observed homozygous variants in two ID candidate genes, GRAMD1B and TBRG1, for which each has been previously reported in a single family. An additional 14 families have homozygous variants in established ID genes, of which 11 variants are novel. All ARID genes have increased expression in specific structures of the developing and adult human brain and 91% of the genes are differentially expressed in utero or during early childhood. The identification of novel ARID candidate genes and variants adds to the knowledge base that is required to further understand human brain function and development.
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http://dx.doi.org/10.1007/s00439-018-1928-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6201268PMC
September 2018

Whole exome sequencing identifies a novel dominant missense mutation underlying leukonychia in a Pakistani family.

J Hum Genet 2018 Oct 23;63(10):1071-1076. Epub 2018 Jul 23.

USTC-SJH Joint Center for Human Reproduction and Genetics, The CAS Key Laboratory of Innate Immunity and Chronic Diseases, Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China (USTC), Collaborative Innovation Center of Genetics and Development, Hefei, 230027, Anhui, China.

Hereditary leukonychia (also known as porcelain nails or white nails) is a genetic disorder. It may exist as an isolated feature or associated with other cutaneous or systemic disorders. Although a number of genes have been described to cause leukonychia, still the underlying genetic etiologies of many cases remain unknown. Here, we report a Pakistani family presenting leukonychia and koilonychia nails in mother and five of her kids. All the affected individuals had white to pale nails in appearance exhibiting complete and partial leukonychia, respectively. Similarly, nails of finger and toe appeared brittle and concave, showing the characteristics features of koilonychia. Whole exome sequencing and subsequent Sanger sequencing identified a pathogenic novel missense mutation (c.1390G>A, p.Glu464Lys) in PLCD1, co-segregating with the disorder in an autosomal dominant pattern. In silico prediction tools supported the pathogenicity of the identified mutation. Literature review determined that mutations in PLCD1 only cause leukonychia. Therefore, our findings add another pathogenic variant to the PLCD1 mutation pool causing leukonychia that would help to understand the underlying molecular mechanism.
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http://dx.doi.org/10.1038/s10038-018-0491-2DOI Listing
October 2018

Molecular and in silico analyses validates pathogenicity of homozygous mutations in the NPR2 gene underlying variable phenotypes of Acromesomelic dysplasia, type Maroteaux.

Int J Biochem Cell Biol 2018 09 18;102:76-86. Epub 2018 Jul 18.

Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, Pakistan. Electronic address:

Homozygous and/or heterozygous loss of function mutations in the natriuretic peptide receptor B (NPR2) have been reported in causing acromesomelic dysplasia, type Maroteaux with variable clinical features and idiopathic short stature with nonspecific skeletal deformities. On the other hand, gain of function mutations in the same gene result in overgrowth disorder suggesting that NPR2 and its ligand, natriuretic peptide precursor C (CNP), are the key players of endochondral bone growth. However, the precise mechanism behind phenotypic variability of the NPR2 mutations is not fully understood so far. In the present study, three consanguineous families of Pakistani origin (A, B, C) with variable phenotypes of acromesomelic dysplasia, type Maroteaux were evaluated at clinical and molecular levels. Linkage analysis followed by Sanger sequencing of the NPR2 gene revealed three homozygous mutations including p.(Leu314 Arg), p.(Arg371*), and p.(Arg1032*) in family A, B and C, respectively. In silico structural and functional analyses substantiated that a novel missense mutation [p.(Leu314 Arg)] in family A allosterically affects binding of NPR2 homodimer to its ligand (CNP) which ultimately results in defective guanylate cyclase activity. A nonsense mutation [p.(Arg371*)] in family B entirely removed the transmembrane domain, protein kinase domain and guanylate cyclase domains of the NPR2 resulting in abolishing its guanylate cyclase activity. Another novel mutation [p.(Arg1032*)], found in family C, deteriorated the guanylate cyclase domain of the protein and probably plundered its guanylate cyclase activity. These results suggest that guanylate cyclase activity is the most critical function of the NPR2 and phenotypic severity of the NPR2 mutations is proportional to the reduction in its guanylate cyclase activity.
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http://dx.doi.org/10.1016/j.biocel.2018.07.004DOI Listing
September 2018

A novel mutation in the HPGD gene causing primary hypertrophic osteoarthropathy with digital clubbing in a Pakistani family.

Ann Hum Genet 2018 05 28;82(3):171-176. Epub 2017 Dec 28.

Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, Khyber Pakhtunkhwa, Pakistan.

Primary hypertrophic osteoarthropathy (PHO) is a congenital multisystemic entity characterized by three major clinical symptoms: pachydermia, periostosis, and digital clubbing. Recently it has been reported that pathogenic mutations in two genes are known to be associated with PHO: HPGD and SLCO2A1. In the present study, a five-generation consanguineous Pakistani family harboring primary hypertrophic osteoarthropathy in autosomal-recessive pattern was ascertained. Whole genome single nucleotide polymorphisms (SNPs) genotyping and sequence analysis revealed a novel homozygous missense mutation (c.577T˃C) of the human HPGD gene in all affected members of the family. The study presented here demonstrate the first case of primary hypertrophic osteoarthropathy reported in Pashtun population.
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http://dx.doi.org/10.1111/ahg.12239DOI Listing
May 2018

Novel sequence variants in the MKKS gene cause Bardet-Biedl syndrome with intra- and inter-familial variable phenotypes.

Congenit Anom (Kyoto) 2018 Sep 22;58(5):173-175. Epub 2017 Dec 22.

Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

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http://dx.doi.org/10.1111/cga.12264DOI Listing
September 2018

Pakistan Genetic Mutation Database (PGMD); A centralized Pakistani mutome data source.

Eur J Med Genet 2018 Apr 7;61(4):204-208. Epub 2017 Dec 7.

Department of Biotechnology & Genetic Engineering, Kohat University of Science & Technology (KUST), Kohat, Khyber Pakhtunkhwa, Pakistan. Electronic address:

The development and advancement of next generation sequencing have not only sped up the process of identifying rare variants, but have also enabled scientists to explore all variants in a single individual. The Pakistani population has a high ratio of first degree consanguinity, which is why it is a rich source for various kinds of genetic disorders. Due to the heterogeneous composition of Pakistani population, the likelihood of genetic heterogeneity for each disorder is high. Therefore, the compilation and organization of such vast genetic data is necessary to facilitate access for analysis and interpretation to researchers and medical geneticists. The increased research on Pakistani ethnic families for disease gene identification has revealed many mutations, which has led us to develop a Pakistani mutome database entitled "Pakistan Genetic Mutation Database (PGMD)". In PGMD, the medico-genetic information about diseases are mainly compiled into Syndromic and Non-syndromic disorders. It is a public database, which can be freely accessed from http://www.pakmutation.com. At present, we have registered more than 1000 mutations, reported in about 130 different kinds of genetic disorders. Practically, PGMD will assist researchers, clinicians, and geneticists in genetic counseling and screening of population-specific mutations, which will also aid in personalized healthcare.
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http://dx.doi.org/10.1016/j.ejmg.2017.11.015DOI Listing
April 2018

Molecular genetic analysis of consanguineous families with primary microcephaly identified pathogenic variants in the ASPM gene.

J Genet 2017 Jun;96(2):383-387

Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha 3050, Qatar.

Autosomal recessive primary microcephaly is a rare genetic disorder that is characterized by reduced head circumference and a varying degree of intellectual disability. Genetic studies on consanguineous families with primary microcephaly have identified 15 (MCPH) causative genes that include MCPH1, WDR62, CDK5RAP2, CASC5, ASPM, CENPJ, STIL, CEP135, CEP152, ZNF335, PHC1, CDK6, CENPE, SASS6 MFSD2A ANKLE2 and CIT (Khan et al. 2014; Yamamoto et al. 2014; Alakbarzade et al. 2015;Morris-Rosendahl and Kaindl 2015; Basit et al. 2016). Physiologically, most of these MCPH proteins are involved in cell cycle and its regulation. In the present clinical genetic study, we have present two consanguineous Pakistani families segregating primary microcephaly and intellectual disability. These families were ascertained from the Saraiki ethnic part of Khyber-Pakhtunkhwa province in Pakistan. Whole exome sequencing in one family revealed a novel 1-bp deletion NM_018136.4: c.10013delA (p.Asp3338Valfs*2), while the other family showed a previously reported nonsense mutation NM_018136.4: c.9730C>T (rs199422195 (p.Arg3244*)) in ASPM gene. The novel frame-shift mutation (p.Asp3338Valfs*2) in ASPM presumably truncates the protein synthesis that results in loss of armadillo-type fold domain.
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http://dx.doi.org/10.1007/s12041-017-0759-xDOI Listing
June 2017

Ophthalmo-genetic analysis of Pakistani patients with nonsyndromic oculocutaneous albinism through whole exome sequencing.

J Pak Med Assoc 2017 May;67(5):790-792

Gomal Centre of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan, KPK, Pakistan.

Oculocutaneous albinism (OCA) is a disorder of defective melanin biosynthesis that is characterized by hypo-pigmentation of skin, hair and retinal pigment epithelium. Phenotypically, OCA patients exhibit white milky skin, whitish to golden hair and deterioration of retinal cells. Until recently, genetic studies have reported seven causative genes (TYR, TYRP1, OCA2, SLC45A2, SLC24A2, C10ORF11 and MCIR) and an uncharacterized OCA5 locus. Herein we present the medico-genetic study of three Pakistani patients inheriting autosomal recessive OCA. Whole exome sequencing, followed by Sanger DNA sequencing for segregation analysis, revealed recurrent mutations c.346C>T (p.Arg116*) and c.1255G>A (p.Gly419Arg) (family A and B respectively) in TYR gene, while the patient from family C did not reveal any known gene mutation, which suggests the involvement of some novel genetic factor. It is the first report of mapping c.346C>T mutation in a Pakistani patient. Our study further extends the evidence of genetic hotspots regions in TYR gene causing OCA in Pakistani population.
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May 2017

A novel mutation in homeobox DNA binding domain of HOXC13 gene underlies pure hair and nail ectodermal dysplasia (ECTD9) in a Pakistani family.

BMC Med Genet 2017 04 12;18(1):42. Epub 2017 Apr 12.

Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan.

Background: Pure hair and nail ectodermal dysplasia (PHNED) is a congenital disorder of hair abnormalities and nail dysplasia. Both autosomal recessive and dominant inheritance fashion of PHNED occurs. In literature, to date, five different forms of PHNED have been reported at molecular level, having three genes known and two loci with no gene yet.

Methods: In this study, a four generations consanguineous family of Pakistani origin with autosomal recessive PHNED was investigated. Affected members exhibited PHNED phenotypes with involvement of complete hair loss and nail dysplasia. To screen for mutation in the genes (HOXC13, KRT74, KRT85), its coding exons and exons-intron boundaries were sequenced. The 3D models of normal and mutated HOXC13 were predicted by using homology modeling.

Results: Through investigating the family to known loci, the family was mapped to ectodermal dysplasia 9 (ECTD9) loci with genetic address of 12q13.13. Mutation screening revealed a novel missense mutation (c.929A > C; p.Asn310Thr) in homeobox DNA binding domain of HOXC13 gene in affected members of the family. Due to mutation, loss of hydrogen bonding and difference in potential energy occurs, which may resulting in alteration of protein function.

Conclusion: This is the first mutation reported in homeodomain, while 5 mutation reported in HOXC13 gene causing PHNED.
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http://dx.doi.org/10.1186/s12881-017-0402-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389142PMC
April 2017

CTX-M-15 and OXA-10 beta lactamases in multi drug resistant Pseudomonas aeruginosa: First report from Pakistan.

Microb Pathog 2017 Apr 28;105:240-244. Epub 2017 Feb 28.

Department of Biotechnology and Genetic Engineering Kohat University of Science & Technology, Kohat, Khyber Pakhtunkhwa, Pakistan. Electronic address:

Background: Pseudomonas aeruginosa is an emerging threat to public health worldwide due to their rapid development of drug resistance including beta-lactamases. The present study was designed to investigate the incidence of β-lactamases and genotypic pattern of CTX and OXA in the clinical isolate of multidrug resistant P. aeruginosa.

Methods: In this study a total of 102 MDR P. aeruginosa isolates obtained from Lady Reading Hospital, Peshawar, Pakistan were subjected to extended spectrum beta lactamase (ESBL), metallo beta lactamase (MBL) and plasmid mediated β-lactamase (AmpC) detection using phenotypic and molecular methods. Furthermore, sequencing of CTX and OXA gene was performed.

Results: Out of 102 MDR P. aeruginosa isolates, 71 (69.6%) were beta lactamase producers. The incidence of ESBL, MBL and AmpC in clinical isolates of P. aeruginosa was found to be 23.94%, 40.84% and 35.21% respectively. Co-production of ESBL and AmpC were also observed in some isolates. There were 14 (19.71%) CTX-M-15 harboring isolates which were ESBL (64.28%), MBL (21.42%) and AmpC (14.28%) producer. Co-production of ESBL/MBL (14.28%), ESBL/AmpC (14.28%) and MBL/AmpC (14.28%) were also observed in the CTX M-15 harboring isolates while 12.28% isolates were not ESBL, MBL or AmpC producer. OXA-10 was detected in 8 (11.26%) isolates which were ESBL (12.5%), MBL (37.5%) and AmpC (12.5%) producer. OXA 10 isolates also exhibit co-production of ESBL/AmpC (12.5%) and MBL/AmpC (12.5%). All CTX-M-15 carried the class A β-lactamase conserved domain while OXA-10 harbored conserved domain of class D β-lactamase.

Conclusion: The current study for the first time reported and characterized the CTX-M-15 and OXA-10 among MDR P. aeruginosa isolates from Pakistan. Further efforts are needed to understand the molecular mechanism of drug resistance with CTX and OXA harboring P. aeruginosa isolates.
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http://dx.doi.org/10.1016/j.micpath.2017.02.039DOI Listing
April 2017

The Molecular Genetics of Autosomal Recessive Nonsyndromic Intellectual Disability: a Mutational Continuum and Future Recommendations.

Ann Hum Genet 2016 Nov;80(6):342-368

Genomic Core Facility, Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, 3050, Qatar.

Intellectual disability (ID) is a clinical manifestation of the central nervous system without any major dysmorphologies of the brain. Biologically it affects learning capabilities, memory, and cognitive functioning. The basic defining features of ID are characterized by IQ<70, age of onset before 18 years, and impairment of at least two of the adaptive skills. Clinically it is classified in a syndromic (with additional abnormalities) and a nonsyndromic form (with only cognitive impairment). The study of nonsyndromic intellectual disability (NSID) can best explain the pathophysiology of cognition, intelligence and memory. Genetic analysis in autosomal recessive nonsyndrmic ID (ARNSID) has mapped 51 disease loci, 34 of which have revealed their defective genes. These genes play diverse physiological roles in various molecular processes, including methylation, proteolysis, glycosylation, signal transduction, transcription regulation, lipid metabolism, ion homeostasis, tRNA modification, ubiquitination and neuromorphogenesis. High-density SNP array and whole exome sequencing has increased the pace of gene discoveries and many new mutations are being published every month. The lack of uniform criteria has assigned multiple identifiers (or accession numbers) to the same MRT locus (e.g. MRT7 and MRT22). Here in this review we describe the molecular genetics of ARNSID, prioritize the candidate genes in uncharacterized loci, and propose a new nomenclature to reorganize the mutation data that will avoid the confusion of assigning duplicate accession numbers to the same ID locus and to make the data manageable in the future as well.
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http://dx.doi.org/10.1111/ahg.12176DOI Listing
November 2016

Hypomorphic MKS1 mutation in a Pakistani family with mild Joubert syndrome and atypical features: Expanding the phenotypic spectrum of MKS1-related ciliopathies.

Am J Med Genet A 2016 12 29;170(12):3289-3293. Epub 2016 Aug 29.

Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

Postaxial polydactyly (PAP) is one of the most common congenital malformations observed in the general population. However, it can also occur as part of a syndrome. Unbiased genetic screening techniques such as exome sequencing are highly appropriate methods to provide a molecular diagnosis in patients with polydactyly due to the large number of mutated genes associated with it. The present study describes a consanguineous family of Pakistani origin with PAP, speech impairment, hearing impairment of variable degree, and proportionate short stature with no prominent intellectual disability or ophthalmological abnormalities. One affected individual of the family was subjected to exome sequencing which resulted in the identification of four homozygous variants including an in-frame deletion (c.1115_1117delCCT; p.(Ser372del) in MKS1, which was later shown to be the only variant segregating with the phenotype. In silico predictions supported the potential pathogenicity of the identified mutation. Additional clinical tests and MRI features of a patient in the family showed a molar tooth sign, which is a hallmark of Joubert syndrome. In conclusion, we have described a pathogenic variant in the MKS1 resulting in a mild Joubert syndrome phenotype, which broadens the spectrum of mutations in the MKS1. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ajmg.a.37934DOI Listing
December 2016

Multisystem Radiologic Manifestations of Erdheim-Chester Disease.

Case Rep Radiol 2016 31;2016:2670495. Epub 2016 May 31.

Department of Radiology, Stony Brook University Hospital, 101 Nicolls Road, Stony Brook, NY 11794, USA.

Erdheim-Chester Disease is a rare form of multiorgan non-Langerhans' cell histiocytosis that affects individuals between the ages of 50 and 70 with an equal distribution among males and females. It is associated with significant morbidity and mortality that is mostly due to infiltration of critical organs. Some of the sites that Erdheim-Chester Disease affects include the skeletal system, central nervous system, cardiovascular system, lungs, kidneys (retroperitoneum), and skin. The most common presenting symptom of Erdheim-Chester Disease is bone pain although a large majority of patients are diagnosed incidentally during a workup for a different disease process. Diagnosing Erdheim-Chester Disease is challenging due its rarity and mimicry to other infiltrative processes. Therefore, a multimodality diagnostic approach is employed with imaging being at the forefront. As of date, a comprehensive radiologic review of the manifestations of Erdheim-Chester Disease has rarely been reported. Here we present radiologic findings of an individual suffering from Erdheim-Chester Disease.
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http://dx.doi.org/10.1155/2016/2670495DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4906176PMC
June 2016

Multi drug resistant Pseudomonas aeruginosa: Pathogen burden and associated antibiogram in a tertiary care hospital of Pakistan.

Microb Pathog 2016 Aug 16;97:209-12. Epub 2016 Jun 16.

Department of Biotechnology and Genetic Engineering, Kohat University of Science & Technology, Kohat, Khyber Pakhtunkhwa, Pakistan. Electronic address:

Pseudomonas aeruginosa is an important pathogen of both community and hospital acquired infections, and a major threat to public health for continuous emergence of multi-drug resistance. Current prevalence and pattern of multidrug resistance in the clinical isolates of P. aeruginosa is reported here. Samples were collected from September 2013 to January 2014 tertiary care hospital, Peshawar. Samples were subjected to phenotypic and molecular based detection of P. aeruginosa and were further processed for multidrug resistance pattern. Out of 3700 samples, 102 were identified as MDR P. aeruginosa. Prevalence of MDR isolates were found in pus (34.3%), wounds (28.4%), urine (19.6%), blood (14.7%) and sputum (2.9%) respectively. Isolates were more resistant to Sulphamethoxazole/Trimethoprim (98.04%), Amoxycillin/Clavulanic acid, Doxycycline and Chloramphenicol (95.1%) each, while least resistant to Imipenem (43.1%), Cefoperazone/Sulbactam (50.98%) and Amikacin (53.9%). Extensive MDR pattern was observed in P. aeruginosa was found as (n = 17, 16.6%) isolates were resistant to all four classes of antibiotics. Increased burden of MDR P. aeruginosa was documented in the study. Moreover, some isolates were even resistant to four classes of antibiotics. Findings of the study will be helpful to devise an appropriate antibiotic treatment strategy against MDR P. aeruginosa to cope the chances of evolving resistant pathogens.
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http://dx.doi.org/10.1016/j.micpath.2016.06.017DOI Listing
August 2016

Genetics of human isolated acromesomelic dysplasia.

Eur J Med Genet 2016 Apr 27;59(4):198-203. Epub 2016 Feb 27.

Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, Pakistan.

Acromesomelic dysplasia is a type of skeletal malformation affecting distal and middle segments of the extremities. It occurs in both isolated (non-syndromic) and syndromic forms. In later case, it shows association with cardiac, respiratory, neurological and genital abnormalities. Acromesomelic dysplasia segregates in autosomal recessive mode. Mutations in three genes (GDF5, NPR2, BMPR1B) have been reported to cause different forms of acromesomelic dysplasia. In the present review, we have discussed clinical spectrum, genetics and signalopathies of isolated acromesomelic dysplasias.
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http://dx.doi.org/10.1016/j.ejmg.2016.02.011DOI Listing
April 2016

Disease causing homozygous variants in the human hairless gene.

Int J Dermatol 2016 Sep 18;55(9):977-81. Epub 2015 Dec 18.

Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

Background: Atrichia with papular lesions (APL) is a rare irreversible form of complete hair loss inherited in autosomal recessive manner. Hair loss is often followed by the appearance of multiple keratin-filled cysts or papules on exterior parts of the body. This phenotype results due to mutations in the human hairless gene (HR) mapped on chromosome 8p21.3. The present study was aimed to search for disease-causing sequence variants in the HR gene in five consanguineous families exhibiting features of APL.

Methods: Linkage in five Pakistani lineal consanguineous families, displaying features of APL, was tested using microsatellite markers flanking the HR gene on chromosome 8p21.3. After constructing the haplotypes, variants in the gene HR were searched by dideoxy-chain termination sequencing.

Results: Haplotype analysis established linkage in all five families to the HR gene located on chromosome 8p.21.3. Subsequently, sequencing HR identified a novel homozygous nonsense variant (c.2541G>A, p.Trp847*) in one and previously reported two pathogenic variants (p.Cys690*, p.Pro1157Arg) in the other four families.

Conclusion: Mutations identified extend the spectrum of mutations in the HR gene resulting in APL. Characterizing the clinical spectrum resulting from the disease-causing homozygous variants in the HR gene will direct clinical care of the family members.
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http://dx.doi.org/10.1111/ijd.13109DOI Listing
September 2016

Homozygous sequence variants in the NPR2 gene underlying Acromesomelic dysplasia Maroteaux type (AMDM) in consanguineous families.

Ann Hum Genet 2015 Jul 11;79(4):238-44. Epub 2015 May 11.

Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, Pakistan.

Acromesomelic dysplasia Maroteaux type (AMDM) is an autosomal recessive skeletal disorder characterized by disproportionate short stature with shortening of the acromesomelic sections of the limbs. AMDM is caused by mutations in the NPR2 gene located on chromosome 9p21-p12. The gene encodes the natriuretic peptide receptor B (NPR-B) that acts as an endogenous receptor for C-type natriuretic peptide (CNP). Both CNP and NPR-B are considered as important regulators of longitudinal growth. The study presented here investigated three consanguineous families (A, B, C) segregating AMDM in an autosomal recessive manner. Linkage in the families was established to the NPR2 gene on chromosome 9p12-21. Sequence analysis of the gene revealed two novel missense variants (p.Arg601Ser; p.Arg749Trp) in two families and a previously reported splice site variant (c.2986+2T>G) in the third family.
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http://dx.doi.org/10.1111/ahg.12116DOI Listing
July 2015