Publications by authors named "Hülya Kayserili"

176 Publications

A Micropatterned Human-Specific Neuroepithelial Tissue for Modeling Gene and Drug-Induced Neurodevelopmental Defects.

Adv Sci (Weinh) 2021 Mar 6;8(5):2001100. Epub 2021 Jan 6.

Department of Biomedical Engineering National University of Singapore Singapore 117583 Singapore.

The generation of structurally standardized human pluripotent stem cell (hPSC)-derived neural embryonic tissues has the potential to model genetic and environmental mediators of early neurodevelopmental defects. Current neural patterning systems have so far focused on directing cell fate specification spatio-temporally but not morphogenetic processes. Here, the formation of a structurally reproducible and highly-organized neuroepithelium (NE) tissue is directed from hPSCs, which recapitulates morphogenetic cellular processes relevant to early neurulation. These include having a continuous, polarized epithelium and a distinct invagination-like folding, where primitive ectodermal cells undergo E-to-N-cadherin switching and apical constriction as they acquire a NE fate. This is accomplished by spatio-temporal patterning of the mesoendoderm, which guides the development and self-organization of the adjacent primitive ectoderm into the NE. It is uncovered that TGF signaling emanating from endodermal cells support tissue folding of the prospective NE. Evaluation of NE tissue structural dysmorphia, which is uniquely achievable in the model, enables the detection of apical constriction and cell adhesion dysfunctions in patient-derived hPSCs as well as differentiating between different classes of neural tube defect-inducing drugs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/advs.202001100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927627PMC
March 2021

Clinical and Molecular Characterization of Fanconi Anemia Patients in Turkey.

Mol Syndromol 2020 Nov 23;11(4):183-196. Epub 2020 Sep 23.

Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.

Fanconi anemia (FA) is a rare multigenic chromosomal instability syndrome that predisposes patients to life-threatening bone marrow failure, congenital malformations, and cancer. Functional loss of interstrand cross-link (ICL) DNA repair system is held responsible, though the mechanism is not yet fully understood. The clinical and molecular findings of 20 distinct FA cases, ages ranging from perinatal stage to 32 years, are presented here. Pathogenic variants in were found responsible in 75%, / in 5%, and / and / in 2.5% of the subjects. Altogether, 25 different variants in 7 different FA genes, including 10 novel mutations in / and / were disclosed. Two compound heterozygous germline cases were mosaic for one allele, revealing that the incidence of reverse mutations may not be uncommon in FA. Another case with de novo and paternally inherited pathogenic alleles at first glance suggested a digenic inheritance, because the presence of a second pathogenic variant in the unexamined regions of and were exluded by sequencing and deletion/duplication analysis. A better understanding of the complexity of the FA genotype may provide further access to undiscovered ICL components and apparently dispensable cellular pathways where FA proteins may play important roles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000509838DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7675230PMC
November 2020

Human model of IRX5 mutations reveals key role for this transcription factor in ventricular conduction.

Cardiovasc Res 2020 Sep 8. Epub 2020 Sep 8.

Université de Nantes, CNRS, INSERM, l'institut du thorax, F-44000 Nantes, France.

Aim: Several inherited arrhythmic diseases have been linked to single gene mutations in cardiac ion channels and interacting proteins. However, the mechanisms underlying most arrhythmias, are thought to involve altered regulation of the expression of multiple effectors. In this study, we aimed to examine the role of a transcription factor belonging to the Iroquois homeobox family, IRX5, in cardiac electrical function.

Methods And Results: Using human cardiac tissues, transcriptomic correlative analyses between IRX5 and genes involved in cardiac electrical activity showed that in human ventricular compartment, IRX5 expression strongly correlated to the expression of major actors of cardiac conduction, including the sodium channel, Nav1.5, and Connexin 40 (Cx40). We then generated human induced pluripotent stem cells (hiPSCs) derived from two Hamamy Syndrome-affected patients carrying distinct homozygous loss-of-function mutations in IRX5 gene. Cardiomyocytes derived from these hiPSCs showed impaired cardiac gene expression program, including misregulation in the control of Nav1.5 and Cx40 expression. In accordance with the prolonged QRS interval observed in Hamamy Syndrome patients, a slower ventricular action potential depolarization due to sodium current reduction was observed on electrophysiological analyses performed on patient-derived cardiomyocytes, confirming the functional role of IRX5 in electrical conduction. Finally, a novel cardiac transcription factor complex was identified, composed by IRX5 and GATA4, in which IRX5 potentiated GATA4-induction of SCN5A expression.

Conclusions: Altogether, this work unveils a key role for IRX5 in the regulation of human ventricular depolarization and cardiac electrical conduction, providing therefore new insights into our understanding of cardiac diseases.

Translational Perspectives: Inherited cardiac arrhythmias account for about 20% of sudden cardiac deaths, of which a small portion are monogenic familial diseases with mutations in cardiac ion channels. However, pathogeny of inherited cardiac arrhythmias is increasingly thought to result from complex mechanisms involving altered regulation of multiple effectors expression. Taking advantage of cardiomyocytes derived from Hamamy syndrome patients, carrying loss-of-function mutations in IRX5 transcription factor, we uncovered an important role for IRX5 in the regulation of several major players of ventricular depolarization conduction and in arrhythmogenesis. Thus, this study supports systematic screening for genetic variants in IRX5 in inherited cardiac arrhythmias.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/cvr/cvaa259DOI Listing
September 2020

A loss-of-function NUAK2 mutation in humans causes anencephaly due to impaired Hippo-YAP signaling.

J Exp Med 2020 12;217(12)

Human Genetics and Embryology Laboratory, Institute of Medical Biology, Agency for Science, Technology and Research, Singapore.

Failure of neural tube closure during embryonic development can result in anencephaly, one of the most common birth defects in humans. A family with recurrent anencephalic fetuses was investigated to understand its etiology and pathogenesis. Exome sequencing revealed a recessive germline 21-bp in-frame deletion in NUAK2 segregating with the disease. In vitro kinase assays demonstrated that the 7-amino acid truncation in NUAK2, a serine/threonine kinase, completely abrogated its catalytic activity. Patient-derived disease models including neural progenitor cells and cerebral organoids showed that loss of NUAK2 activity led to decreased Hippo signaling via cytoplasmic YAP retention. In neural tube-like structures, endogenous NUAK2 colocalized apically with the actomyosin network, which was disrupted in patient cells, causing impaired nucleokinesis and apical constriction. Our results establish NUAK2 as an indispensable kinase for brain development in humans and suggest that a NUAK2-Hippo signaling axis regulates cytoskeletal processes that govern cell shape during neural tube closure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1084/jem.20191561DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953732PMC
December 2020

Characteristic dental pattern with hypodontia and short roots in Fraser syndrome.

Am J Med Genet A 2020 07 2;182(7):1681-1689. Epub 2020 Jun 2.

Institute of Human Genetics, University Hospital, Magdeburg, Germany.

Fraser syndrome (FS) is a rare autosomal recessive multiple congenital malformation syndrome characterized by cryptophthalmos, cutaneous syndactyly, renal agenesis, ambiguous genitalia, and laryngotracheal anomalies. It is caused by biallelic mutations of FRAS1, FREM2, and GRIP1 genes, encoding components of a protein complex that mediates embryonic epithelial-mesenchymal interactions. Anecdotal reports have described abnormal orodental findings in FS, but no study has as yet addressed the orodental findings of FS systematically. We reviewed dental radiographs of 10 unrelated patients with FS of different genetic etiologies. Dental anomalies were present in all patients with FS and included hypodontia, dental crowding, medial diastema, and retained teeth. A very consistent pattern of shortened dental roots of most permanent teeth as well as altered length/width ratio with shortened dental crowns of upper incisors was also identified. These findings suggest that the FRAS1-FREM complex mediates critical mesenchymal-epithelial interactions during dental crown and root development. The orodental findings of FS reported herein represent a previously underestimated manifestation of the disorder with significant impact on orodental health for affected individuals. Integration of dentists and orthodontists into the multidisciplinary team for management of FS is therefore recommended.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.61610DOI Listing
July 2020

A novel shoulder disability staging system for scapulothoracic arthrodesis in patients with facioscapulohumeral dystrophy.

Orthop Traumatol Surg Res 2020 Jun 16;106(4):701-707. Epub 2020 May 16.

Koc University, School of Medicine, Department of Orthopaedics and Traumatology, Koc Universitesi Hastanesi, Davutpasa Cd. No:4 Topkapi-Zeytinburnu, 34010 Istanbul Turkey.

Background: Scapulothoracic arthrodesis (STA) is a well-established surgical technique to provide scapular stabilisation in patients with facioscapulohumeral dystrophy (FSHD). There is no staging or scoring systems available to guide surgical decision. The aim of this study was to develop a staging system to evaluate the shoulder disability in patients with FSHD to guide surgical decision-making and assess its reliability among surgeons.

Methods: Fifty-seven shoulders of 29 patients (15 male, 14 female) with an average age of 34.5 years (13-73) were included. Six stages of the disease were defined to create a system consisting of shoulder elevation, deltoid function and scapular winging. Patients were assessed by two independent orthopaedic surgeons who were blind to each other. Statistical analyses included mean and standard deviation for descriptive variables, Pearson's correlation and Cohen's Kappa for inter- and intraobserver agreement.

Results: Measurement of elevation showed excellent correlation in both inter- and intraobserver assessment. There was substantial agreement on deltoid function and moderate agreement on scapular winging. Decisions on stage showed excellent agreement on interobserver and substantial agreement on intraobserver assessment. Surgical decision using the stage showed excellent agreement on both inter- and intraobserver assessment.

Conclusion: This novel staging system has an excellent inter observer agreement on FSHD patients' shoulder disability. This would provide surgeons a beneficial tool to define patient groups that would have negatively or positively affected from STA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.otsr.2020.03.002DOI Listing
June 2020

Loss of PYCR2 Causes Neurodegeneration by Increasing Cerebral Glycine Levels via SHMT2.

Neuron 2020 07 23;107(1):82-94.e6. Epub 2020 Apr 23.

Institute of Medical Biology, Human Genetics and Embryology Laboratory, A(∗)STAR, Singapore 138648, Singapore; Genome Institute of Singapore, A∗STAR, Singapore 138672, Singapore; Institute of Molecular and Cellular Biology, A(∗)STAR, Singapore 138673, Singapore; Department of Medical Genetics, Koç University, School of Medicine, 34010 Istanbul, Turkey; Department of Paediatrics, National University of Singapore, Singapore 119260, Singapore. Electronic address:

Patients lacking PYCR2, a mitochondrial enzyme that synthesizes proline, display postnatal degenerative microcephaly with hypomyelination. Here we report the crystal structure of the PYCR2 apo-enzyme and show that a novel germline p.Gly249Val mutation lies at the dimer interface and lowers its enzymatic activity. We find that knocking out Pycr2 in mice phenocopies the human disorder and depletes PYCR1 levels in neural lineages. In situ quantification of neurotransmitters in the brains of PYCR2 mutant mice and patients revealed a signature of encephalopathy driven by excessive cerebral glycine. Mechanistically, we demonstrate that loss of PYCR2 upregulates SHMT2, which is responsible for glycine synthesis. This hyperglycemia could be partially reversed by SHMT2 knockdown, which rescued the axonal beading and neurite lengths of cultured Pycr2 knockout neurons. Our findings identify the glycine metabolic pathway as a possible intervention point to alleviate the neurological symptoms of PYCR2-mutant patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neuron.2020.03.028DOI Listing
July 2020

Clinical exome sequencing in neuromuscular diseases: an experience from Turkey.

Neurol Sci 2020 Aug 5;41(8):2157-2164. Epub 2020 Mar 5.

Medical Genetics Department, Koç University School of Medicine (KUSoM), 34010, Istanbul, Turkey.

Neuromuscular diseases (NMDs) encompass a variety of ailments from muscular dystrophies to ataxias, in the course of which the functioning of the muscles is eventually either directly or indirectly impaired. The clinical diagnosis of a particular NMD is not always straightforward due to the clinical and genetic heterogeneity of the disorders under investigation. Traditional diagnostic tools such as electrophysiological tests and muscle biopsies are both invasive and painful methods, causing the patients to be reluctant. Next-generation sequencing, on the other hand, emerged as an alternative method for the diagnosis of NMDs, both with its minimally invasive nature and fast processing period. In this study, clinical exome sequencing (CES) was applied to a cohort of 70 probands in Turkey, 44 of whom received a final diagnosis, representing a diagnostic rate of 62.9%. Out of the 50 mutations identified to be causal, 26 were novel in the known 27 NMD genes. Two probands had complex/blended phenotypes. Molecular confirmation of clinical diagnosis of NMDs has a major prognostic impact and is crucial for the management and the possibility of alternative reproductive options. CES, which has been increasingly adopted to diagnose single-gene disorders, is also a powerful tool for revealing the etiopathogenesis in complex/blended phenotypes, as observed in two probands of the cohort.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10072-020-04304-wDOI Listing
August 2020

Zoledronate-responsive calcitriol-mediated hypercalcemia in a 5-year-old case with squamous cell carcinoma on the background of xeroderma pigmentosum.

J Pediatr Endocrinol Metab 2019 Dec;32(12):1403-1406

Division of Pediatric Endocrinology, Department of Pediatrics, Koc University School of Medicine, Istanbul, Turkey.

Malignancy-induced hypercalcemia is a very rare condition in children whereas it is more common among adult patients with malignancy. The mechanisms of malignancy-induced hypercalcemia include the over-secretion of parathyroid hormone-related protein (PTHrP), osteolytic metastases and the over-production of 1,25-dihydroxyvitamin D (calcitriol). Although hypercalcemia due to PTHrP secretion has been published before, overproduction of calcitriol has not been reported yet in pediatric squamous cell skin carcinoma cases. Herein, we report calcitriol-mediated severe hypercalcemia in a 5-year-old boy with squamous cell skin carcinoma arising in the background of xeroderma pigmentosum (XP) which responded well to zoledronate treatment. To the best of our knowledge, this is the first pediatric case of malignancy-induced hypercalcemia which is mediated by calcitriol in squamous cell skin carcinoma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1515/jpem-2019-0158DOI Listing
December 2019

TMX2 Is a Crucial Regulator of Cellular Redox State, and Its Dysfunction Causes Severe Brain Developmental Abnormalities.

Am J Hum Genet 2019 12 14;105(6):1126-1147. Epub 2019 Nov 14.

Department of Clinical Genetics, Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands. Electronic address:

The redox state of the neural progenitors regulates physiological processes such as neuronal differentiation and dendritic and axonal growth. The relevance of endoplasmic reticulum (ER)-associated oxidoreductases in these processes is largely unexplored. We describe a severe neurological disorder caused by bi-allelic loss-of-function variants in thioredoxin (TRX)-related transmembrane-2 (TMX2); these variants were detected by exome sequencing in 14 affected individuals from ten unrelated families presenting with congenital microcephaly, cortical polymicrogyria, and other migration disorders. TMX2 encodes one of the five TMX proteins of the protein disulfide isomerase family, hitherto not linked to human developmental brain disease. Our mechanistic studies on protein function show that TMX2 localizes to the ER mitochondria-associated membranes (MAMs), is involved in posttranslational modification and protein folding, and undergoes physical interaction with the MAM-associated and ER folding chaperone calnexin and ER calcium pump SERCA2. These interactions are functionally relevant because TMX2-deficient fibroblasts show decreased mitochondrial respiratory reserve capacity and compensatory increased glycolytic activity. Intriguingly, under basal conditions TMX2 occurs in both reduced and oxidized monomeric form, while it forms a stable dimer under treatment with hydrogen peroxide, recently recognized as a signaling molecule in neural morphogenesis and axonal pathfinding. Exogenous expression of the pathogenic TMX2 variants or of variants with an in vitro mutagenized TRX domain induces a constitutive TMX2 polymerization, mimicking an increased oxidative state. Altogether these data uncover TMX2 as a sensor in the MAM-regulated redox signaling pathway and identify it as a key adaptive regulator of neuronal proliferation, migration, and organization in the developing brain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2019.10.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6904804PMC
December 2019

Heterozygous pathogenic variants in GLI1 are a common finding in isolated postaxial polydactyly A/B.

Hum Mutat 2020 01 6;41(1):265-276. Epub 2019 Nov 6.

Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Madrid, Spain.

Postaxial polydactyly (PAP) is a frequent limb malformation consisting in the duplication of the fifth digit of the hand or foot. Morphologically, this condition is divided into type A and B, with PAP-B corresponding to a more rudimentary extra-digit. Recently, biallelic truncating variants in the transcription factor GLI1 were reported to be associated with a recessive disorder, which in addition to PAP-A, may include syndromic features. Moreover, two heterozygous subjects carrying only one inactive copy of GLI1 were also identified with PAP. Herein, we aimed to determine the level of involvement of GLI1 in isolated PAP, a condition previously established to be autosomal dominantly inherited with incomplete penetrance. We analyzed the coding region of GLI1 in 95 independent probands with nonsyndromic PAP and found 11.57% of these subjects with single heterozygous pathogenic variants in this gene. The detected variants lead to premature termination codons or result in amino acid changes in the DNA-binding domain of GLI1 that diminish its transactivation activity. Family segregation analysis of these variants was consistent with dominant inheritance with incomplete penetrance. We conclude that heterozygous changes in GLI1 underlie a significant proportion of sporadic or familial cases of isolated PAP-A/B.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/humu.23921DOI Listing
January 2020

A rare cause of chronic hyponatremia in an infant: Answers.

Pediatr Nephrol 2020 02 19;35(2):243-245. Epub 2019 Aug 19.

Division of Pediatric Nephrology, Department of Pediatrics, Koç University School of Medicine, Davutpaşa cad no:4 Topkapı, 34010, Istanbul, Turkey.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00467-019-04337-0DOI Listing
February 2020

A rare cause of chronic hyponatremia in an infant: Questions.

Pediatr Nephrol 2020 02 19;35(2):241-242. Epub 2019 Aug 19.

Division of Pediatric Nephrology, Department of Pediatrics, Koç University School of Medicine, Davutpaşa cad no:4 Topkapı, 34010, Istanbul, Turkey.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00467-019-04335-2DOI Listing
February 2020

Cohesin complex-associated holoprosencephaly.

Brain 2019 09;142(9):2631-2643

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.

Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven research, 80-90% of aneuploidy-negative holoprosencephaly individuals with a probable genetic aetiology do not have a genetic diagnosis. Here we report holoprosencephaly associated with variants in the two X-linked cohesin complex genes, STAG2 and SMC1A, with loss-of-function variants in 10 individuals and a missense variant in one. Additionally, we report four individuals with variants in the cohesin complex genes that are not X-linked, SMC3 and RAD21. Using whole mount in situ hybridization, we show that STAG2 and SMC1A are expressed in the prosencephalic neural folds during primary neurulation in the mouse, consistent with forebrain morphogenesis and holoprosencephaly pathogenesis. Finally, we found that shRNA knockdown of STAG2 and SMC1A causes aberrant expression of HPE-associated genes ZIC2, GLI2, SMAD3 and FGFR1 in human neural stem cells. These findings show the cohesin complex as an important regulator of median forebrain development and X-linked inheritance patterns in holoprosencephaly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awz210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245359PMC
September 2019

European recommendations integrating genetic testing into multidisciplinary management of sudden cardiac death.

Eur J Hum Genet 2019 12 24;27(12):1763-1773. Epub 2019 Jun 24.

Section Community Genetics, Department of Clinical Genetics and Amsterdam Public Health research institute, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.

Sudden cardiac death (SCD) accounts for 10-20% of total mortality, i.e., one in five individuals will eventually die suddenly. Given the substantial genetic component of SCD in younger cases, postmortem genetic testing may be particularly useful in elucidating etiological factors in the cause of death in this subset. The identification of genes responsible for inherited cardiac diseases have led to the organization of cardiogenetic consultations in many countries worldwide. Expert recommendations are available, emphasizing the importance of genetic testing and appropriate information provision of affected individuals, as well as their relatives. However, the context of postmortem genetic testing raises some particular ethical, legal, and practical (including economic or financial) challenges. The Public and Professional Policy Committee of the European Society of Human Genetics (ESHG), together with international experts, developed recommendations on management of SCD after a workshop sponsored by the Brocher Foundation and ESHG in November 2016. These recommendations have been endorsed by the ESHG Board, the European Council of Legal Medicine, the European Society of Cardiology working group on myocardial and pericardial diseases, the ERN GUARD-HEART, and the Association for European Cardiovascular Pathology. They emphasize the importance of increasing the proportion of both medical and medicolegal autopsies and educating the professionals. Multidisciplinary collaboration is of utmost importance. Public funding should be allocated to reach these goals and allow public health evaluation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41431-019-0445-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6870982PMC
December 2019

Turkish Ectodermal Dysplasia Cohort: From Phenotype to Genotype in 17 Families.

Cytogenet Genome Res 2019 12;157(4):189-196. Epub 2019 Apr 12.

Hypohidrotic or anhidrotic ectodermal dysplasia (HED/EDA) is characterized by impaired development of the hair, teeth, or sweat glands. HED/EDA is inherited in an X-linked, autosomal dominant, or autosomal recessive pattern and caused by the pathogenic variants in 4 genes: EDA, EDAR, EDARADD, and WNT10A. The aim of the present study was to perform molecular screening of these 4 genes in a cohort of Turkish individuals diagnosed with HED/EDA. We screened for pathogenic variants of WNT10A, EDA, EDAR, and EDARADD through Sanger sequencing. We further assessed the clinical profiles of the affected individuals in order to establish phenotype-genotype correlation. In 17 (63%) out of 27 families, 17 pathogenic variants, 8 being novel, were detected in the 4 well-known ectodermal dysplasia genes. EDAR and EDA variants were identified in 6 families each, WNT10A variants in 4, and an EDARADD variant in 1, accounting for 35.3, 35.3, 23.5, and 5.9% of mutation-positive families, respectively. The low mutation detection rate of the cohort and the number of the EDAR pathogenic variants being as high as the EDA ones were the most noteworthy findings which could be attributed to the high consanguinity rate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000499325DOI Listing
July 2019

Correction: The ARID1B spectrum in 143 patients: from nonsyndromic intellectual disability to Coffin-Siris syndrome.

Authors:
Pleuntje J van der Sluijs Sandra Jansen Samantha A Vergano Miho Adachi-Fukuda Yasemin Alanay Adila AlKindy Anwar Baban Allan Bayat Stefanie Beck-Wödl Katherine Berry Emilia K Bijlsma Levinus A Bok Alwin F J Brouwer Ineke van der Burgt Philippe M Campeau Natalie Canham Krystyna Chrzanowska Yoyo W Y Chu Brain H Y Chung Karin Dahan Marjan De Rademaeker Anne Destree Tracy Dudding-Byth Rachel Earl Nursel Elcioglu Ellen R Elias Christina Fagerberg Alice Gardham Blanca Gener Erica H Gerkes Ute Grasshoff Arie van Haeringen Karin R Heitink Johanna C Herkert Nicolette S den Hollander Denise Horn David Hunt Sarina G Kant Mitsuhiro Kato Hülya Kayserili Rogier Kersseboom Esra Kilic Malgorzata Krajewska-Walasek Kylin Lammers Lone W Laulund Damien Lederer Melissa Lees Vanesa López-González Saskia Maas Grazia M S Mancini Carlo Marcelis Francisco Martinez Isabelle Maystadt Marianne McGuire Shane McKee Sarju Mehta Kay Metcalfe Jeff Milunsky Seiji Mizuno John B Moeschler Christian Netzer Charlotte W Ockeloen Barbara Oehl-Jaschkowitz Nobuhiko Okamoto Sharon N M Olminkhof Carmen Orellana Laurent Pasquier Caroline Pottinger Vera Riehmer Stephen P Robertson Maian Roifman Caroline Rooryck Fabienne G Ropers Monica Rosello Claudia A L Ruivenkamp Mahmut S Sagiroglu Suzanne C E H Sallevelt Amparo Sanchis Calvo Pelin O Simsek-Kiper Gabriela Soares Lucia Solaeche Fatma Mujgan Sonmez Miranda Splitt Duco Steenbeek Alexander P A Stegmann Constance T R M Stumpel Saori Tanabe Eyyup Uctepe G Eda Utine Hermine E Veenstra-Knol Sunita Venkateswaran Catheline Vilain Catherine Vincent-Delorme Anneke T Vulto-van Silfhout Patricia Wheeler Golder N Wilson Louise C Wilson Bernd Wollnik Tomoki Kosho Dagmar Wieczorek Evan Eichler Rolph Pfundt Bert B A de Vries Jill Clayton-Smith Gijs W E Santen

Genet Med 2019 Sep;21(9):2160-2161

Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands.

The original version of this Article contained an error in the spelling of the author Pleuntje J. van der Sluijs, which was incorrectly given as Eline (P. J.) van der Sluijs. This has now been corrected in both the PDF and HTML versions of the Article.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-018-0368-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752317PMC
September 2019

A homozygous pathogenic missense variant broadens the phenotypic and mutational spectrum of CREB3L1-related osteogenesis imperfecta.

Hum Mol Genet 2019 06;28(11):1801-1809

Center for Medical Genetics Ghent, Ghent University Hospital, Department of Biomolecular Medicine, Ghent, Belgium.

The cyclic adenosine monophosphate responsive element binding protein 3-like 1 (CREB3L1) gene codes for the endoplasmic reticulum stress transducer old astrocyte specifically induced substance (OASIS), which has an important role in osteoblast differentiation during bone development. Deficiency of OASIS is linked to a severe form of autosomal recessive osteogenesis imperfecta (OI), but only few patients have been reported. We identified the first homozygous pathogenic missense variant [p.(Ala304Val)] in a patient with lethal OI, which is located within the highly conserved basic leucine zipper domain, four amino acids upstream of the DNA binding domain. In vitro structural modeling and luciferase assays demonstrate that this missense variant affects a critical residue in this functional domain, thereby decreasing the type I collagen transcriptional binding ability. In addition, overexpression of the mutant OASIS protein leads to decreased transcription of the SEC23A and SEC24D genes, which code for components of the coat protein complex type II (COPII), and aberrant OASIS signaling also results in decreased protein levels of SEC24D. Our findings therefore provide additional proof of the potential involvement of the COPII secretory complex in the context of bone-associated disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddz017DOI Listing
June 2019

Terminal osseous dysplasia with pigmentary defects (TODPD) in a Turkish girl with new skin findings.

Am J Med Genet A 2019 01 18;179(1):123-129. Epub 2018 Dec 18.

Medical Genetics Department, Koç University School of Medicine (KUSoM), İstanbul, Turkey.

Terminal osseous dysplasia with pigmentary defects (TODPD; MIM #300244) is an extremely rare, X-linked dominant, in utero male-lethal disease, characterized by skeletal dysplasia of the limbs, pigmentary defects of the skin, and recurrent digital fibromatosis of childhood. Delayed/abnormal ossification of bones of the hands and feet, joint contractures, and dysmorphic facial features may accompany. A single recurrent mutation (c.5217 G>A) of the FLNA gene which causes cryptic splicing was identified as the cause of the disease. We here present the first TODPD case from Turkey with full-blown phenotype who exhibit unique additional findings, hypopigmented patch on the lower extremity following Blaschko's lines and smooth muscle hamartoma of the scalp in review of all the previously reported TODPD cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.60686DOI Listing
January 2019

The oculoauriculofrontonasal syndrome: Further clinical characterization and additional evidence suggesting a nontraditional mode of inheritance.

Am J Med Genet A 2018 12 10;176(12):2740-2750. Epub 2018 Dec 10.

Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, Centre Hospitalier Universitaire Dijon, Dijon, France.

The oculoauriculofrontonasal syndrome (OAFNS) is a rare disorder characterized by the association of frontonasal dysplasia (widely spaced eyes, facial cleft, and nose abnormalities) and oculo-auriculo-vertebral spectrum (OAVS)-associated features, such as preauricular ear tags, ear dysplasia, mandibular asymmetry, epibulbar dermoids, eyelid coloboma, and costovertebral anomalies. The etiology is unknown so far. This work aimed to identify molecular bases for the OAFNS. Among a cohort of 130 patients with frontonasal dysplasia, accurate phenotyping identified 18 individuals with OAFNS. We describe their clinical spectrum, including the report of new features (micro/anophtalmia, cataract, thyroid agenesis, polymicrogyria, olfactory bulb hypoplasia, and mandibular cleft), and emphasize the high frequency of nasal polyps in OAFNS (56%). We report the negative results of ALX1, ALX3, and ALX4 genes sequencing and next-generation sequencing strategy performed on blood-derived DNA from respectively, four and four individuals. Exome sequencing was performed in four individuals, genome sequencing in one patient with negative exome sequencing result. Based on the data from this series and the literature, diverse hypotheses can be raised regarding the etiology of OAFNS: mosaic mutation, epigenetic anomaly, oligogenism, or nongenetic cause. In conclusion, this series represents further clinical delineation work of the rare OAFNS, and paves the way toward the identification of the causing mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.40662DOI Listing
December 2018

Sclerosing bone dysplasias with hallmarks of dysosteosclerosis in four patients carrying mutations in SLC29A3 and TCIRG1.

Bone 2019 03 8;120:495-503. Epub 2018 Dec 8.

Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Max Planck Institute for Molecular Genetics, Berlin, Germany; Berlin-Brandenburg Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany. Electronic address:

The osteopetroses and related sclerosing bone dysplasias can have a broad range of manifestations. Especially in the milder forms, sandwich vertebrae are an easily recognizable and reliable radiological hallmark. We report on four patients from three families presenting with sandwich vertebrae and platyspondyly. The long bone phenotypes were discordant with one patient showing modeling defects and patchy osteosclerosis, while the second displayed only metaphyseal sclerotic bands, and the third and fourth had extreme metaphyseal flaring with uniform osteosclerosis. Two of the four patients had experienced pathological fractures, two had developmental delay, but none showed cranial nerve damage, hepatosplenomegaly, or bone marrow failure. According to these clinical features the diagnoses ranged between intermediate autosomal recessive osteopetrosis and dysosteosclerosis. After exclusion of mutations in CLCN7 we performed gene panel and exome sequencing. Two novel mutations in SLC29A3 were found in the first two patients. In the third family a TCIRG1 C-terminal frameshift mutation in combination with a mutation at position +4 in intron 2 were detected. Our study adds two cases to the small group of individuals with SLC29A3 mutations diagnosed with dysosteosclerosis, and expands the phenotypic variability. The finding that intermediate autosomal recessive osteopetrosis due to TCIRG1 splice site mutations can also present with platyspondyly further increases the molecular heterogeneity of dysosteosclerosis-like sclerosing bone dysplasias.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bone.2018.12.002DOI Listing
March 2019

MAB21L1 loss of function causes a syndromic neurodevelopmental disorder with distinctive erebellar, cular, cranioacial and enital features (COFG syndrome).

J Med Genet 2019 05 28;56(5):332-339. Epub 2018 Nov 28.

Genome Research Division, Human Genetics Department, Radboud University Medical Center, Nijmegen, The Netherlands.

Background: Putative nucleotidyltransferase MAB21L1 is a member of an evolutionarily well-conserved family of the male abnormal 21 (MAB21)-like proteins. Little is known about the biochemical function of the protein; however, prior studies have shown essential roles for several aspects of embryonic development including the eye, midbrain, neural tube and reproductive organs.

Objective: A homozygous truncating variant in has recently been described in a male affected by intellectual disability, scrotal agenesis, ophthalmological anomalies, cerebellar hypoplasia and facial dysmorphism. We employed a combination of exome sequencing and homozygosity mapping to identify the underlying genetic cause in subjects with similar phenotypic features descending from five unrelated consanguineous families.

Results: We identified four homozygous loss of function variants (p.Glu281fs*20, p.Arg287Glufs*14 p.Tyr280* and p.Ser93Serfs*48) and one missense variant (p.Gln233Pro) in 10 affected individuals from 5 consanguineous families with a distinctive autosomal recessive neurodevelopmental syndrome. Cardinal features of this syndrome include a characteristic facial gestalt, corneal dystrophy, hairy nipples, underdeveloped labioscrotal folds and scrotum/scrotal agenesis as well as cerebellar hypoplasia with ataxia and variable microcephaly.

Conclusion: This report defines an ultrarare but clinically recognisable Cerebello-Oculo-Facio-Genital syndrome associated with recessive variants. Additionally, our findings further support the critical role of MAB21L1 in cerebellum, lens, genitalia and as craniofacial morphogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jmedgenet-2018-105623DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6581149PMC
May 2019

An unusual cause of nephrotic syndrome: Answers.

Pediatr Nephrol 2019 05 7;34(5):819-821. Epub 2018 Nov 7.

Istanbul Faculty of Medicine, Pediatric Nephrology Department, Istanbul University, Istanbul, Turkey.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00467-018-4115-zDOI Listing
May 2019

An unusual cause of nephrotic syndrome: Questions.

Pediatr Nephrol 2019 05 7;34(5):817-818. Epub 2018 Nov 7.

Istanbul Faculty of Medicine, Pediatric Nephrology Department, Istanbul University, Istanbul, Turkey.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00467-018-4113-1DOI Listing
May 2019

The ARID1B spectrum in 143 patients: from nonsyndromic intellectual disability to Coffin-Siris syndrome.

Authors:
Pleuntje J van der Sluijs Sandra Jansen Samantha A Vergano Miho Adachi-Fukuda Yasemin Alanay Adila AlKindy Anwar Baban Allan Bayat Stefanie Beck-Wödl Katherine Berry Emilia K Bijlsma Levinus A Bok Alwin F J Brouwer Ineke van der Burgt Philippe M Campeau Natalie Canham Krystyna Chrzanowska Yoyo W Y Chu Brain H Y Chung Karin Dahan Marjan De Rademaeker Anne Destree Tracy Dudding-Byth Rachel Earl Nursel Elcioglu Ellen R Elias Christina Fagerberg Alice Gardham Blanca Gener Erica H Gerkes Ute Grasshoff Arie van Haeringen Karin R Heitink Johanna C Herkert Nicolette S den Hollander Denise Horn David Hunt Sarina G Kant Mitsuhiro Kato Hülya Kayserili Rogier Kersseboom Esra Kilic Malgorzata Krajewska-Walasek Kylin Lammers Lone W Laulund Damien Lederer Melissa Lees Vanesa López-González Saskia Maas Grazia M S Mancini Carlo Marcelis Francisco Martinez Isabelle Maystadt Marianne McGuire Shane McKee Sarju Mehta Kay Metcalfe Jeff Milunsky Seiji Mizuno John B Moeschler Christian Netzer Charlotte W Ockeloen Barbara Oehl-Jaschkowitz Nobuhiko Okamoto Sharon N M Olminkhof Carmen Orellana Laurent Pasquier Caroline Pottinger Vera Riehmer Stephen P Robertson Maian Roifman Caroline Rooryck Fabienne G Ropers Monica Rosello Claudia A L Ruivenkamp Mahmut S Sagiroglu Suzanne C E H Sallevelt Amparo Sanchis Calvo Pelin O Simsek-Kiper Gabriela Soares Lucia Solaeche Fatma Mujgan Sonmez Miranda Splitt Duco Steenbeek Alexander P A Stegmann Constance T R M Stumpel Saori Tanabe Eyyup Uctepe G Eda Utine Hermine E Veenstra-Knol Sunita Venkateswaran Catheline Vilain Catherine Vincent-Delorme Anneke T Vulto-van Silfhout Patricia Wheeler Golder N Wilson Louise C Wilson Bernd Wollnik Tomoki Kosho Dagmar Wieczorek Evan Eichler Rolph Pfundt Bert B A de Vries Jill Clayton-Smith Gijs W E Santen

Genet Med 2019 06 8;21(6):1295-1307. Epub 2018 Nov 8.

Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands.

Purpose: Pathogenic variants in ARID1B are one of the most frequent causes of intellectual disability (ID) as determined by large-scale exome sequencing studies. Most studies published thus far describe clinically diagnosed Coffin-Siris patients (ARID1B-CSS) and it is unclear whether these data are representative for patients identified through sequencing of unbiased ID cohorts (ARID1B-ID). We therefore sought to determine genotypic and phenotypic differences between ARID1B-ID and ARID1B-CSS. In parallel, we investigated the effect of different methods of phenotype reporting.

Methods: Clinicians entered clinical data in an extensive web-based survey.

Results: 79 ARID1B-CSS and 64 ARID1B-ID patients were included. CSS-associated dysmorphic features, such as thick eyebrows, long eyelashes, thick alae nasi, long and/or broad philtrum, small nails and small or absent fifth distal phalanx and hypertrichosis, were observed significantly more often (p < 0.001) in ARID1B-CSS patients. No other significant differences were identified.

Conclusion: There are only minor differences between ARID1B-ID and ARID1B-CSS patients. ARID1B-related disorders seem to consist of a spectrum, and patients should be managed similarly. We demonstrated that data collection methods without an explicit option to report the absence of a feature (such as most Human Phenotype Ontology-based methods) tended to underestimate gene-related features.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-018-0330-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752273PMC
June 2019

A multidisciplinary clinical approach to facioscapulohumeral muscular dystrophy.

Ideggyogy Sz 2018 Sep;71(9-10):337-342

Koç University, School of Medicine, Department of Neurology, Istanbul, Turkey.

Background And Purpose: Impaired shoulder function is the most disabling problem for daily life of Fascioscapulohumeral muscular dystrophy (FSHD) patients. Scapulothoracic arthrodesis can give a high impact to the functionality of patients. Here we report our experience with scapulothoracic arthrodesis and spinal stenosis surgery in FSHD patients.

Methods: 32 FSHD patients were collected between 2015-2016. Demographical and clinical features were documented. All the patients were neurologically examined. The Medical Research Council (MRC) and the FSHD evaluation scale was used to assess muscle involvement1. Scapulothoracic arthrodesis and spinal stenosis surgeries were performed in eligible patients.

Results: There were 16 male and 16 female (mean age 34.4 years; range 12-73) patients. 6 shoulders of 4 patients aged between 2132 years underwent scapulothoracic arthrodesis (two bilateral, one left and one right sided). Only one 63 years old female patient with severe hyperlordosis had spinal fusion surgery. All of the patients undergoing these corrective surgeries have better functionality in daily life, as well as superior shoulder elevation.

Conclusion: Until the emergence and clinical use of novel therapeutics, surgical interventions are indicated in carefully selected patients with FSHD to improve arm movements, the posture and the quality of life of patients in general. Scapulothorosic arthrodesis is a management with good clinical results and patient satisfaction. In selected cases other corrective orthopedic surgeries like spinal fusion may also be considered.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18071/isz.71.0337DOI Listing
September 2018

Recontacting patients in clinical genetics services: recommendations of the European Society of Human Genetics.

Eur J Hum Genet 2019 02 11;27(2):169-182. Epub 2018 Oct 11.

Clinical Genetics Department, Guy's & St. Thomas' NHS Foundation Trust, London, UK.

Technological advances have increased the availability of genomic data in research and the clinic. If, over time, interpretation of the significance of the data changes, or new information becomes available, the question arises as to whether recontacting the patient and/or family is indicated. The Public and Professional Policy Committee of the European Society of Human Genetics (ESHG), together with research groups from the UK and the Netherlands, developed recommendations on recontacting which, after public consultation, have been endorsed by ESHG Board. In clinical genetics, recontacting for updating patients with new, clinically significant information related to their diagnosis or previous genetic testing may be justifiable and, where possible, desirable. Consensus about the type of information that should trigger recontacting converges around its clinical and personal utility. The organization of recontacting procedures and policies in current health care systems is challenging. It should be sustainable, commensurate with previously obtained consent, and a shared responsibility between healthcare providers, laboratories, patients, and other stakeholders. Optimal use of the limited clinical resources currently available is needed. Allocation of dedicated resources for recontacting should be considered. Finally, there is a need for more evidence, including economic and utility of information for people, to inform which strategies provide the most cost-effective use of healthcare resources for recontacting.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41431-018-0285-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6336881PMC
February 2019

Variants affecting diverse domains of MEPE are associated with two distinct bone disorders, a craniofacial bone defect and otosclerosis.

Genet Med 2019 05 5;21(5):1199-1208. Epub 2018 Oct 5.

Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.

Purpose: To characterize new molecular factors implicated in a hereditary congenital facial paresis (HCFP) family and otosclerosis.

Methods: We performed exome sequencing in a four-generation family presenting nonprogressive HCFP and mixed hearing loss (HL). MEPE was analyzed using either Sanger sequencing or molecular inversion probes combined with massive parallel sequencing in 89 otosclerosis families, 1604 unrelated affected subjects, and 1538 unscreened controls.

Results: Exome sequencing in the HCFP family led to the identification of a rare segregating heterozygous frameshift variant p.(Gln425Lysfs*38) in MEPE. As the HL phenotype in this family resembled otosclerosis, we performed variant burden and variance components analyses in a large otosclerosis cohort and demonstrated that nonsense and frameshift MEPE variants were significantly enriched in affected subjects (p = 0.0006-0.0060).

Conclusion: MEPE exerts its function in bone homeostasis by two domains, an RGD and an acidic serine aspartate-rich MEPE-associated (ASARM) motif inhibiting respectively bone resorption and mineralization. All variants associated with otosclerosis are predicted to result in nonsense mediated decay or an ASARM-and-RGD-truncated MEPE. The HCFP variant is predicted to produce an ASARM-truncated MEPE with an intact RGD motif. This difference in effect on the protein corresponds with the presumed pathophysiology of both diseases, and provides a plausible molecular explanation for the distinct phenotypic outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-018-0300-5DOI Listing
May 2019

Pallister-Killian syndrome: clinical, cytogenetic and molecular findings in 15 cases.

Mol Cytogenet 2018 17;11:45. Epub 2018 Aug 17.

1Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Millet cad.34039 Capa, İstanbul, Turkey.

Background: Pallister Killian syndrome (PKS, OMIM 601803) is a rare genetic disorder with a distinct phenotype caused by tissue- limited mosaicism tetrasomy of the short arm of chromosome 12, which usually cytogenetically presents as an extra isochromosome 12p.Wide phenotypic variability in PKS has been reported, ranging from pre-to perinatal death due to multiple congenital anomalies, especially diaphragmatic hernia, and classic phenotypes including seizures, severe developmental delay, macrosomia at birth, deafness, and distinct dysmorphic features, such as coarse face, temporal alopecia, a small nose with anteverted nostrils, long philtrum, and hypo-/hyper- pigmented streaks on the skin.

Results: Karyotypes obtained from cultured peripheral lymphocytes of 13 cases, who were diagnosed as PKS, were normal, while karyotypes obtained from cultured skin samples and buccal mucosa revealed the supernumerary mosaic i(12p). Mosaic karyotype was found in both fibroblast and buccal mucosa in 14 of 15 patients in our series, whereas in one stillbirth, following the clinical diagnosis of PKS, skin and buccal smear samples were taken, and all karyotypes from cultured fibroblasts revealed a supernumerary i(12p), while I-FISH study showed 60% mosaicism in mucosal cells.

Conclusions: We here share the clinical, cytogenetic and molecular cytogenetic findings of 15 cases with PKS phenotype and the parental origin of seven i(12p) identified by molecular analyses. To our knowledge, this is the largest series of PKS patients with parental origin study from a single center. We believe that our study makes a significant contribution to the literature because we specifically found no differences in the phenotypes of cases with either a maternal or paternal origin of the extra element and differential imprinting appeared not to be a factor.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13039-018-0395-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6098576PMC
August 2018

Identification of likely pathogenic and known variants in TSPEAR, LAMB3, BCOR, and WNT10A in four Turkish families with tooth agenesis.

Hum Genet 2018 Sep 26;137(9):689-703. Epub 2018 Jul 26.

Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Millet Cad., Capa, Fatih, 34093, Istanbul, Turkey.

Tooth agenesis (TA), the failure of development of one or more permanent teeth, is a common craniofacial abnormality observed in different world populations. The genetic etiology of TA is heterogeneous; more than a dozen genes have been associated with isolated or nonsyndromic TA, and more than 80 genes with syndromic forms. In this study, we applied whole exome sequencing (WES) to identify candidate genes contributing to TA in four Turkish families. Likely pathogenic variants with a low allele frequency in the general population were identified in four disease-associated genes, including two distinct variants in TSPEAR, associated with syndromic and isolated TA in one family each; a variant in LAMB3 associated with syndromic TA in one family; and a variant in BCOR plus a disease-associated WNT10A variant in one family with syndromic TA. With the notable exception of WNT10A (Tooth agenesis, selective, 4, MIM #150400), the genotype-phenotype relationships described in the present cohort represent an expansion of the clinical spectrum associated with these genes: TSPEAR (Deafness, autosomal recessive 98, MIM #614861), LAMB3 (Amelogenesis imperfecta, type IA, MIM #104530; Epidermolysis bullosa, junctional, MIMs #226700 and #226650), and BCOR (Microphthalmia, syndromic 2, MIM #300166). We provide evidence supporting the candidacy of these genes with TA, and propose TSPEAR as a novel nonsyndromic TA gene. Our data also suggest potential multilocus genomic variation, or mutational burden, in a single family, involving the BCOR and WNT10A loci, underscoring the complexity of the genotype-phenotype relationship in the common complex trait of TA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00439-018-1907-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6165673PMC
September 2018