Publications by authors named "Teresa Mattina"

42 Publications

A case series of adult patients affected by EAST/SeSAME syndrome suggests more severe disease in subjects bearing truncating mutations.

Intractable Rare Dis Res 2021 May;10(2):95-101

Biogem Research Institute, Ariano Irpino, Italy.

EAST/SeSAME syndrome is a rare disease affecting the Central Nervous System (CNS), inner ear, and kidney. The syndrome is due to loss-of-function mutations in the gene encoding the inward-rectifying potassium channel Kir4.1. EAST/SeSAME syndrome is mainly diagnosed during childhood with a tonic-clonic seizure being the usual first symptom. Due to a limited number of patients and recent identification of the disease, few data are available on the clinical progress of this disease in adulthood. In particular, neurologic and nephrological outcomes have not been reported. We present a case series of 4 adult patients harbouring homozygous missense mutation p.Ala167Val and homozygous frameshift mutations p.Asn232Glnfs*14 and p.Gly275Valfs*7. Effects of these mutations were predicted by modelling and bioinformatic tools. Patients with truncating mutations were associated with more severe outcomes, both in tubulopathy severity and neurological symptomatology. Conversely, either missense or truncating mutations were correlated with similar severity of epilepsy, with a long free-of-event period up to 20 years old. No eGFR decline was documented. Modelling predicted that truncating mutations lead to complete Kir4.1 dysfunction. Finally, all patients had a mild increase in urinary protein excretion. Our study indicates that the prognosis of patients suffering from EAST/SeSAME syndrome is related to the severity of the mutation causing the disease. As predicted by modelling, truncating mutations of are associated with more severe disease, with recurrence of symptomatic hypokalemia and more severe neurological phenotype. The type of mutation should be considered for the therapy tailored to patients' phenotype.
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http://dx.doi.org/10.5582/irdr.2020.03158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8122315PMC
May 2021

Copy number variation analysis implicates novel pathways in patients with oculo-auriculo-vertebral-spectrum and congenital heart defects.

Clin Genet 2021 09 24;100(3):268-279. Epub 2021 May 24.

Department of Pediatrics, Obstetrics and Gynecology, "Sapienza" University of Rome, Rome, Italy.

Oculo-auriculo-vertebral spectrum (OAVS) is a developmental disorder of craniofacial morphogenesis. Its etiology is unclear, but assumed to be complex and heterogeneous, with contribution of both genetic and environmental factors. We assessed the occurrence of copy number variants (CNVs) in a cohort of 19 unrelated OAVS individuals with congenital heart defect. Chromosomal microarray analysis identified pathogenic CNVs in 2/19 (10.5%) individuals, and CNVs classified as variants of uncertain significance in 7/19 (36.9%) individuals. Remarkably, two subjects had small intragenic CNVs involving DACH1 and DACH2, two paralogs coding for key components of the PAX-SIX-EYA-DACH network, a transcriptional regulatory pathway controlling developmental processes relevant to OAVS and causally associated with syndromes characterized by craniofacial involvement. Moreover, a third patient showed a large duplication encompassing DMBX1/OTX3, encoding a transcriptional repressor of OTX2, another transcription factor functionally connected to the DACH-EYA-PAX network. Among the other relevant CNVs, a deletion encompassing HSD17B6, a gene connected with the retinoic acid signaling pathway, whose dysregulation has been implicated in craniofacial malformations, was also identified. Our findings suggest that CNVs affecting gene dosage likely contribute to the genetic heterogeneity of OAVS, and implicate the PAX-SIX-EYA-DACH network as novel pathway involved in the etiology of this developmental trait.
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http://dx.doi.org/10.1111/cge.13994DOI Listing
September 2021

Familiar osteopoikilosis: Case report with differential diagnosis and review of the literature.

Clin Case Rep 2021 Feb 24;9(2):922-926. Epub 2020 Dec 24.

Department of Clinical and Experimental Medicine University of Catania Catania Italy.

Osteopoikilosis (OP) is a rare autosomal dominant sclerosing bone disease, caused by heterozygous mutations in the LEMD3 gene. It is characterised by numerous focal lamellar bone compact deposits in the spongiosa. In this case report, we describe a famliar case of OP and review the literature.
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http://dx.doi.org/10.1002/ccr3.3611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7869386PMC
February 2021

When to test fetuses for RASopathies? Proposition from a systematic analysis of 352 multicenter cases and a postnatal cohort.

Genet Med 2021 06 10;23(6):1116-1124. Epub 2021 Feb 10.

Pediatrics Department, Medical Genetics Division, CHU Sainte-Justine, Montreal, QC, Canada.

Purpose: Recent studies have identified suggestive prenatal features of RASopathies (e.g., increased nuchal translucency [NT], cystic hygroma [CH], hydrops, effusions, congenital heart diseases [CHD], polyhydramnios, renal anomalies). Our objective is to clarify indications for RASopathy prenatal testing. We compare genotype distributions between pre- and postnatal populations and propose genotype-phenotype correlations.

Methods: Three hundred fifty-two chromosomal microarray-negative cases sent for prenatal RASopathy testing between 2012 and 2019 were collected. For most, 11 RASopathy genes were tested. Postnatal cohorts (25 patients with available prenatal information and 108 institutional database genotypes) and the NSeuroNet database were used for genotypic comparisons.

Results: The overall diagnostic yield was 14% (50/352), with rates >20% for effusions, hydrops, and CHD. Diagnostic yield was significantly improved in presence of hypertrophic cardiomyopathy (HCM), persistent or associated CH, any suggestive finding combined with renal anomaly or polyhydramnios, or ≥2 ultrasound findings. Largest prenatal contributors of pathogenic variants were PTPN11 (30%), RIT1 (16%), RAF1 (14%), and HRAS (12%), which considerably differ from their prevalence in postnatal populations. HRAS, LZTR1, and RAF1 variants correlated with hydrops/effusions, and RIT1 with prenatal onset HCM.

Conclusion: After normal chromosomal microarray, RASopathies should be considered when any ultrasound finding of lymphatic dysplasia or suggestive CHD is found alone or in association.
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http://dx.doi.org/10.1038/s41436-020-01093-7DOI Listing
June 2021

Genome-Wide DNA Methylation Analysis of a Cohort of 41 Patients Affected by Oculo-Auriculo-Vertebral Spectrum (OAVS).

Int J Mol Sci 2021 Jan 26;22(3). Epub 2021 Jan 26.

Istituto Auxologico Italiano IRCCS, Bioinformatics and Statistical Genomics Unit, Cusano Milanino, 20095 Milano, Italy.

Oculo-auriculo-vertebral-spectrum (OAVS; OMIM 164210) is a rare disorder originating from abnormal development of the first and second branchial arch. The clinical phenotype is extremely heterogeneous with ear anomalies, hemifacial microsomia, ocular defects, and vertebral malformations being the main features. , , and gene variants were reported in a few OAVS patients, but the etiology remains largely unknown. A multifactorial origin has been proposed, including the involvement of environmental and epigenetic mechanisms. To identify the epigenetic mechanisms contributing to OAVS, we evaluated the DNA-methylation profiles of 41 OAVS unrelated affected individuals by using a genome-wide microarray-based methylation approach. The analysis was first carried out comparing OAVS patients with controls at the group level. It revealed a moderate epigenetic variation in a large number of genes implicated in basic chromatin dynamics such as DNA packaging and protein-DNA organization. The alternative analysis in individual profiles based on the searching for Stochastic Epigenetic Variants (SEV) identified an increased number of SEVs in OAVS patients compared to controls. Although no recurrent deregulated enriched regions were found, isolated patients harboring suggestive epigenetic deregulations were identified. The recognition of a different DNA methylation pattern in the OAVS cohort and the identification of isolated patients with suggestive epigenetic variations provide consistent evidence for the contribution of epigenetic mechanisms to the etiology of this complex and heterogeneous disorder.
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http://dx.doi.org/10.3390/ijms22031190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7866060PMC
January 2021

Deciphering the pathogenesis of the COL4-related hematuric nephritis: A genotype/phenotype study.

Mol Genet Genomic Med 2021 02 24;9(2):e1576. Epub 2020 Dec 24.

Medical Genetics, University Hospital of Parma, Parma, Italy.

Background: Alport syndrome (ATS) is a hereditary progressive hematuric nephropathy associated with sensorineural deafness and ocular abnormalities, which is caused by mutations in the COL4A5 gene (X-linked ATS) and in two autosomal genes, COL4A4 and COL4A3, responsible of both recessive ATS and, when present in heterozygosity, of a spectrum of phenotypes ranging from isolated hematuria to frank renal disease.

Methods: Retrospective analysis of the clinical and genetic features of 76 patients from 34 unrelated ATS families (11 with mutations in COL4A5, 11 in COL4A3, and 12 in COL4A4) and genotype/phenotype correlation for the COL4A3/COL4A4 heterozygotes (34 patients from 14 families).

Results: Eight (24%) of the 34 heterozygous COL4A3 and COL4A4 carriers developed renal failure at a mean age of 57 years, with a significantly lower risk than hemizygous COL4A5 or double heterozygous COL4A3/COL4A4 carriers (p < 0.01), but not different from that of the heterozygous COL4A5 females (p = 0.6). Heterozygous carriers of frameshift/splicing variants in COL4A3/COL4A4 presented a higher risk of developing renal failure than those with missense variants in the glycine domains (p = 0.015).

Conclusion: The renal functional prognosis of patients with COL4A3/COL4A4-positive ATS recapitulates that of the X-linked ATS forms, with differences between heterozygous vs. double heterozygous patients and between carriers of loss-of-function vs. missense variants.
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http://dx.doi.org/10.1002/mgg3.1576DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8077073PMC
February 2021

Expanding the phenotype of Wiedemann-Steiner syndrome: Craniovertebral junction anomalies.

Am J Med Genet A 2020 12 11;182(12):2877-2886. Epub 2020 Oct 11.

Medical Genetics Unit, Meyer Children's University Hospital, Florence, Italy.

Wiedemann-Steiner syndrome (WDSTS) is a rare autosomal dominant condition caused by heterozygous loss of function variants in the KMT2A (MLL) gene, encoding a lysine N-methyltransferase that mediates a histone methylation pattern specific for epigenetic transcriptional activation. WDSTS is characterized by a distinctive facial phenotype, hypertrichosis, short stature, developmental delay, intellectual disability, congenital malformations, and skeletal anomalies. Recently, a few patients have been reported having abnormal skeletal development of the cervical spine. Here we describe 11 such individuals, all with KMT2A de novo loss-of-function variants: 10 showed craniovertebral junction anomalies, while an 11th patient had a cervical abnormality in C7. By evaluating clinical and diagnostic imaging data we characterized these anomalies, which consist primarily of fused cervical vertebrae, C1 and C2 abnormalities, small foramen magnum and Chiari malformation type I. Craniovertebral anomalies in WDSTS patients have been largely disregarded so far, but the increasing number of reports suggests that they may be an intrinsic feature of this syndrome. Specific investigation strategies should be considered for early identification and prevention of craniovertebral junction complications in WDSTS patients.
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http://dx.doi.org/10.1002/ajmg.a.61859DOI Listing
December 2020

A Customized Next-Generation Sequencing-Based Panel to Identify Novel Genetic Variants in Dementing Disorders: A Pilot Study.

Neural Plast 2020 18;2020:8078103. Epub 2020 Aug 18.

Oasi Research Institute-IRCCS, Troina, Italy.

Purpose: The advancements in the next-generation sequencing (NGS) techniques have allowed for rapid, efficient, and cost-time-effective genetic variant detection. However, in both clinical practice and research setting, sequencing is still often limited to the use of gene panels clinically targeted on the genes underlying the disease of interest.

Methods: We performed a neurogenetic study through an NGS-based custom sequencing gene panel in order to screen 16 genes in 8 patients with different types of degenerative cognitive disorders (Alzheimer's disease, mild cognitive impairment, frontotemporal dementia, and dementia associated with Parkinson's disease). The study protocol was based on previous evidence showing a high sensitivity and specificity of the technique even when the panel is limited to some hotspot exons.

Results: We found variants of the and genes in three patients; these have been previously identified as pathogenic or likely pathogenic and, therefore, considered "disease causing." In the remaining subjects, the pathogenicity was evaluated according to the guidelines of the American College of Medical Genetics (ACMG). In one patient, the p.R205W variant in the gene was found to be likely pathogenic of the disease. A variant in the and genes found in two patients was classified as benign, whereas the other two (in the and genes) were classified as likely pathogenic according to the ACMG.

Conclusions: Notwithstanding the preliminary value of this study, some rare genetic variants with a probable disease association were detected. Although future application of NGS-based sensors and further replication of these experimental data are needed, this approach seems to offer promising translational perspectives in the diagnosis and management of a wide range of neurodegenerative disorders.
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http://dx.doi.org/10.1155/2020/8078103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7450320PMC
August 2021

Clinical correlates in children with autism spectrum disorder and CNVs: Systematic investigation in a clinical setting.

Int J Dev Neurosci 2020 Jun 25;80(4):276-286. Epub 2020 Mar 25.

Child Neuropsychiatry Unit, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy.

Autism spectrum disorder (ASD) is associated with various molecular mechanisms including copy number variants (CNVs). We investigated possible associations between CNVs and ASD clinical correlates. We evaluated pertinent physical characteristics and phenotypic measures such as cognitive level, severity of ASD symptoms and comorbid conditions in ASD patients consecutively recruited over the study period. Children with causative (C-CNVs), non-causative (NC-CNVs) and without CNVs (W-CNVs) were compared. Out of 109 patients, 31 imbalances (16 duplications and 15 deletions) were detected in 25 subjects. Seven (6.4%) had C-CNVs and 18 (16.5%) had NC-CNVs. Paired post hoc comparisons with Bonferroni adjustment showed that dysmorphisms and microcephaly were significantly more frequent in the C-CNVs group. Patients with C-CNVs had more severe autistic core symptoms, while comorbid internalizing behavioral symptoms were more represented among participants with NC-CNVs. No significant differences were observed for distribution of macrocephaly, intellectual disability, epilepsy, isolated electroencephalogram abnormalities and studied neuroimaging characteristics among groups. Recurrent and rare C-CNVs highlighting genes relevant to neurodevelopment had a statistically higher occurrence in children with more severe ASD symptoms and further developmental abnormalities. This study documents the importance of measuring the physical and neurobehavioural correlates of ASD phenotypes to unravel the underlying molecular mechanisms in patient subgroups.
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http://dx.doi.org/10.1002/jdn.10024DOI Listing
June 2020

Phenotypic Expansion in Nasu-Hakola Disease: Immunological Findings in Three Patients and Proposal of a Unifying Pathogenic Hypothesis.

Front Immunol 2019 23;10:1685. Epub 2019 Jul 23.

Unit of Medical Genetics, Department of Molecular Medicine, University of Pavia, Pavia, Italy.

Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder characterized by progressive presenile dementia and bone cysts, caused by variants in either or . Despite the well-researched role of TREM2 and TYROBP/DAP12 in immunity, immunological phenotypes have never been reported in NHD patients. We initially diagnosed an Italian patient, using whole exome sequencing, with classical NHD clinical sequelae who additionally showed a decrease in NK cells and autoimmunity features underlined by the presence of autoantibodies. Based on this finding, we retrospectively explored the immunophenotype in another two NHD patients, in whom a low NK cell count and positive autoantibody serology were recorded. Accordingly, mice show abnormal levels of circulating proinflammatory cytokines and the dysfunction of immune cells, whereas knockout mice for , encoding the adapter for TREM2, exhibit increased levels of autoantibodies and defective NK cell activity. Our findings tend to redefine NHD as a multisystem "immunological" disease, considering that osteoclasts are derived from the fusion of mononuclear myeloid precursors, whereas neurological anomalies in NHD are directly caused by microglia dysfunction.
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http://dx.doi.org/10.3389/fimmu.2019.01685DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664049PMC
November 2020

Partial trisomy 21 map: Ten cases further supporting the highly restricted Down syndrome critical region (HR-DSCR) on human chromosome 21.

Mol Genet Genomic Med 2019 08 25;7(8):e797. Epub 2019 Jun 25.

Neonatology Unit, Department of Medical and Surgical Sciences (DIMEC), St. Orsola-Malpighi Polyclinic, University of Bologna, Bologna (BO), Italy.

Background: Down syndrome (DS) is characterized by the presence of an extra full or partial human chromosome 21 (Hsa21). An invaluable model to define genotype-phenotype correlations in DS is the study of the extremely rare cases of partial (segmental) trisomy 21 (PT21), the duplication of only a delimited region of Hsa21 associated or not to DS. A systematic retrospective reanalysis of 125 PT21 cases described up to 2015 allowed the creation of the most comprehensive PT21 map and the identification of a 34-kb highly restricted DS critical region (HR-DSCR) as the minimal region whose duplication is shared by all PT21 subjects diagnosed with DS. We reanalyzed at higher resolution three cases previously published and we accurately searched for any new PT21 reports in order to verify whether HR-DSCR limits could prospectively be confirmed and possibly refined.

Methods: Hsa21 partial duplications of three PT21 subjects were refined by adding array-based comparative genomic hybridization data. Seven newly described PT21 cases fulfilling stringent cytogenetic and clinical criteria have been incorporated into the PT21 integrated map.

Results: The PT21 map now integrates fine structure of Hsa21 sequence intervals of 132 subjects onto a common framework fully consistent with the presence of a duplicated HR-DSCR, on distal 21q22.13 sub-band, only in DS subjects and not in non-DS individuals. No documented exception to the HR-DSCR model was found.

Conclusions: The findings presented here further support the association of the HR-DSCR with the diagnosis of DS, representing an unbiased validation of the original model. Further studies are needed to identify and characterize genetic determinants presumably located in the HR-DSCR and functionally associated to the critical manifestations of DS.
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http://dx.doi.org/10.1002/mgg3.797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6687668PMC
August 2019

Melorheostosis and Osteopoikilosis Clinical and Molecular Description of an Italian Case Series.

Calcif Tissue Int 2019 Aug 25;105(2):215-221. Epub 2019 May 25.

Department of Medical Genetics and Rare Orthopaedic Diseases & CLIBI Laboratory, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy.

Melorheostosis (MEL) is an uncommon, sclerosing disease, characterised by hyperostosis of long bones, resembling the flowing of candle wax. The disease is sporadic and the pathogenesis is still poorly understood. Occasionally, the same family can include individuals with MEL and Osteopoikilosis (OPK), a disease characterised by multiple round foci of increased bone density. LEMD3 gene mutations are related to OPK and Buschke-Ollendorff Syndrome, a genetic condition in which an association between MEL, OPK and skin lesions is observed. In rare cases, LEMD3 mutations and recently mosaic MAP2K1 gene mutations have been correlated to MEL suggesting that somatic mosaicism could be causative of the disease. In this study, we described the clinical, radiological and molecular findings of 19 individuals with MEL and 8 with OPK and compared the results to the medical literature. The molecular analyses of this case series corroborate the available data in the medical literature, indicating that LEMD3 germline mutations are not a major cause of isolated MEL and reporting five further cases of OPK caused by LEMD3 germline mutations.
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http://dx.doi.org/10.1007/s00223-019-00565-6DOI Listing
August 2019

Mutational spectrum and clinical signatures in 114 families with hereditary multiple osteochondromas: insights into molecular properties of selected exostosin variants.

Hum Mol Genet 2019 07;28(13):2133-2142

Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy.

Hereditary multiple osteochondromas (HMO) is a rare autosomal dominant skeletal disorder, caused by heterozygous variants in either EXT1 or EXT2, which encode proteins involved in the biogenesis of heparan sulphate. Pathogenesis and genotype-phenotype correlations remain poorly understood. We studied 114 HMO families (158 affected individuals) with causative EXT1 or EXT2 variants identified by Sanger sequencing, or multiplex ligation-dependent probe amplification and qPCR. Eighty-seven disease-causative variants (55 novel and 32 known) were identified including frameshift (42%), nonsense (32%), missense (11%), splicing (10%) variants and genomic rearrangements (5%). Informative clinical features were available for 42 EXT1 and 27 EXT2 subjects. Osteochondromas were more frequent in EXT1 as compared to EXT2 patients. Anatomical distribution of lesions showed significant differences based on causative gene. Microscopy analysis for selected EXT1 and EXT2 variants verified that EXT1 and EXT2 mutants failed to co-localize each other and loss Golgi localization by surrounding the nucleus and/or assuming a diffuse intracellular distribution. In a cell viability study, cells expressing EXT1 and EXT2 mutants proliferated more slowly than cells expressing wild-type proteins. This confirms the physiological relevance of EXT1 and EXT2 Golgi co-localization and the key role of these proteins in the cell cycle. Taken together, our data expand genotype-phenotype correlations, offer further insights in the pathogenesis of HMO and open the path to future therapies.
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http://dx.doi.org/10.1093/hmg/ddz046DOI Listing
July 2019

Biallelic intragenic duplication in ADGRB3 (BAI3) gene associated with intellectual disability, cerebellar atrophy, and behavioral disorder.

Eur J Hum Genet 2019 04 18;27(4):594-602. Epub 2019 Jan 18.

Oasi Research Institute-IRCCS, Troina, Italy.

In recent years, chromosomal microarray analysis has permitted the discovery of rearrangements underlying several neurodevelopmental disorders and still represents the first diagnostic test for unexplained neurodevelopmental disabilities. Here we report a family of consanguineous parents showing psychiatric disorders and their two sons both affected by intellectual disability, ataxia, and behavioral disorder. SNP/CGH array analysis in this family demonstrated in both siblings a biallelic duplication inherited from the heterozygous parents, disrupting the ADGRB3 gene. ADGRB3, also known as BAI3, belongs to the subfamily of adhesion G protein-coupled receptors (adhesion GPCRs) that regulate many aspects of the central nervous system, including axon guidance, myelination, and synapse formation. Single nucleotide polymorphisms and copy number variants involving ADGRB3 have recently been associated with psychiatric disorders. These findings further support this association and also suggest that biallelic variants affecting the function of the ADGRB3 gene may also cause cognitive impairments and ataxia.
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http://dx.doi.org/10.1038/s41431-018-0321-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460634PMC
April 2019

Gene-targeted deletion in mice of the Ets-1 transcription factor, a candidate gene in the Jacobsen syndrome kidney "critical region," causes abnormal kidney development.

Am J Med Genet A 2019 01 13;179(1):71-77. Epub 2018 Nov 13.

Division of Pediatric Cardiology, University of California San Diego School of Medicine, San Diego, California.

Ets-1 is a member of the Ets family of transcription factors and has critical roles in multiple biological functions. Structural kidney defects occur at an increased frequency in Jacobsen syndrome (OMIM #147791), a rare chromosomal disorder caused by deletions in distal 11q, implicating at least one causal gene in distal 11q. In this study, we define an 8.1 Mb "critical region" for kidney defects in Jacobsen syndrome, which spans ~50 genes. We demonstrate that gene-targeted deletion of Ets-1 in mice results in some of the most common congenital kidney defects occurring in Jacobsen syndrome, including: duplicated kidney, hypoplastic kidney, and dilated renal pelvis and calyces. Taken together, our results implicate Ets-1 in normal mammalian kidney development and, potentially, in the pathogenesis of some of the most common types of human structural kidney defects.
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http://dx.doi.org/10.1002/ajmg.a.40481DOI Listing
January 2019

Small supernumerary marker chromosomes: A legacy of trisomy rescue?

Hum Mutat 2019 02 22;40(2):193-200. Epub 2018 Nov 22.

Department of Molecular Medicine, University of Pavia, Pavia, Italy.

We studied by a whole genomic approach and trios genotyping, 12 de novo, nonrecurrent small supernumerary marker chromosomes (sSMC), detected as mosaics during pre- or postnatal diagnosis and associated with increased maternal age. Four sSMCs contained pericentromeric portions only, whereas eight had additional non-contiguous portions of the same chromosome, assembled together in a disordered fashion by repair-based mechanisms in a chromothriptic event. Maternal hetero/isodisomy was detected with a paternal origin of the sSMC in some cases, whereas in others two maternal alleles in the sSMC region and biparental haplotypes of the homologs were detected. In other cases, the homologs were biparental while the sSMC had the same haplotype of the maternally inherited chromosome. These findings strongly suggest that most sSMCs are the result of a multiple-step mechanism, initiated by maternal meiotic nondisjunction followed by postzygotic anaphase lagging of the supernumerary chromosome and its subsequent chromothripsis.
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http://dx.doi.org/10.1002/humu.23683DOI Listing
February 2019

Small 4p16.3 deletions: Three additional patients and review of the literature.

Am J Med Genet A 2018 11 23;176(11):2501-2508. Epub 2018 Sep 23.

Medical Genetics Unit and Laboratory of Medical Genetics, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy.

Wolf-Hirschhorn syndrome is a well-defined disorder due to 4p16.3 deletion, characterized by distinct facial features, intellectual disability, prenatal and postnatal growth retardation, and seizures. Genotype-phenotype correlations based on differently sized deletions have been attempted, and some candidate genes have been suggested. We report on clinical characteristics of three patients with pure interstitial submicroscopic 4p16.3 deletions, ranging in size from 68 to 166 kb, involving WHSCR1 and/or part of WHSCR2, and review published cases with overlapping 4p16.3 losses. The present study highlights a major role of NSD2 gene in the pathogenesis of the WHS main features and predicts that loss-of-function mutations affecting NSD2 gene could result in microcephaly, prenatal and postnatal growth retardation, psychomotor and language delay, and craniofacial features. Absent seizures in all subjects corroborate the suggestion that this specific feature is causally linked with at least one additional causative gene. Finally, we suggest that mir-943 could play a role in the pathogenesis of CHD in some of these patients.
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http://dx.doi.org/10.1002/ajmg.a.40512DOI Listing
November 2018

Rare variants in the genetic background modulate cognitive and developmental phenotypes in individuals carrying disease-associated variants.

Genet Med 2019 04 7;21(4):816-825. Epub 2018 Sep 7.

CHU Nantes, Medical genetics department, Nantes, France.

Purpose: To assess the contribution of rare variants in the genetic background toward variability of neurodevelopmental phenotypes in individuals with rare copy-number variants (CNVs) and gene-disruptive variants.

Methods: We analyzed quantitative clinical information, exome sequencing, and microarray data from 757 probands and 233 parents and siblings who carry disease-associated variants.

Results: The number of rare likely deleterious variants in functionally intolerant genes ("other hits") correlated with expression of neurodevelopmental phenotypes in probands with 16p12.1 deletion (n=23, p=0.004) and in autism probands carrying gene-disruptive variants (n=184, p=0.03) compared with their carrier family members. Probands with 16p12.1 deletion and a strong family history presented more severe clinical features (p=0.04) and higher burden of other hits compared with those with mild/no family history (p=0.001). The number of other hits also correlated with severity of cognitive impairment in probands carrying pathogenic CNVs (n=53) or de novo pathogenic variants in disease genes (n=290), and negatively correlated with head size among 80 probands with 16p11.2 deletion. These co-occurring hits involved known disease-associated genes such as SETD5, AUTS2, and NRXN1, and were enriched for cellular and developmental processes.

Conclusion: Accurate genetic diagnosis of complex disorders will require complete evaluation of the genetic background even after a candidate disease-associated variant is identified.
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http://dx.doi.org/10.1038/s41436-018-0266-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6405313PMC
April 2019

SOX2: Not always eye malformations. Severe genital but no major ocular anomalies in a female patient with the recurrent c.70del20 variant.

Eur J Med Genet 2018 Jun 31;61(6):335-340. Epub 2018 Jan 31.

Department of Molecular Medicine, University of Pavia, Pavia, Italy.

SOX2 variants have been identified in multiple patients with severe ocular anomalies and pituitary dysfunction, in addition to various systemic features. We investigated a 26-year-old female patient suffering from spastic paraparesis, hypoplasia of corpus callosum, hypogonadotropic hypogonadism (HH) and intellectual disability, who was monitored for over 20 years, allowing a detailed genotype-phenotype correlation along time. Whole exome sequencing on the patient and her relatives identified a de novo SOX2 c.70del20 variant, which has been frequently reported in individuals with SOX2-related anophthalmia. Importantly, our patient lacked major ocular phenotype but showed vaginal agenesis, a feature never reported before. Although the involvement of male urogenital tract (cryptorchidism, hypospadias, small penis), is a well known consequence of SOX2 variants, their effect on the female genitalia has never been properly addressed, even considering the paradoxical female excess of SOX2 cases in the literature. Our findings emphasize the importance of testing for SOX2 variants in individuals with HH and genital anomalies even though anophthalmia or microphthalmia are not observed. Moreover, our case strengthens the role of SOX2 as a master regulator of female gonadal differentiation, as widely demonstrated for other SOX genes related to 46, XX sex reversal, such as SOX3 and SOX9.
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http://dx.doi.org/10.1016/j.ejmg.2018.01.011DOI Listing
June 2018

Molecular cytogenetics characterization of seven small supernumerary marker chromosomes derived from chromosome 19: Genotype-phenotype correlation and review of the literature.

Eur J Med Genet 2018 Mar 23;61(3):173-180. Epub 2017 Nov 23.

Lab. di Citogenetica Medica e Amb. di Genetica Medica, IRCCS Istituto Auxologico Italiano, Milano, Italy.

Only a few subjects carrying supernumerary marker chromosomes derived from 19 chromosome (sSMC(19)) have been described to date and for a small portion of them the genic content has been defined at the molecular level. We present seven new different sSMCs(19) identified in eight individuals, seven of whom unrelated. The presence of the sSMC is associated with a clinical phenotype in five subjects, while the other three carriers, two of whom related, are normal. All sSMCs(19) have been characterized by means of conventional and molecular cytogenetics. We compare the sSMCs(19) carriers with a clinical phenotype to already described patients with gains (sSMCs or microduplications) of overlapping genomic regions with the aim to deepen the pathogenicity of the encountered imbalances and to assess the role of the involved genes on the phenotype. The present work supports the correlation between the gain of some chromosome 19 critical regions and specific phenotypes.
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http://dx.doi.org/10.1016/j.ejmg.2017.11.007DOI Listing
March 2018

Early Motor Delay: An Outstanding, Initial Sign of Osteogenesis Imperfecta Type 1.

J Orthop Case Rep 2017 May-Jun;7(3):63-66

Department of Orthopaedics and Traumatologic Surgery, Ospedaliero - Universitaria Policlinico-Vittorio Emanuele, University of Catania, Catania, Italy.

Introduction: Osteogenesis imperfect (OI) is a heterogeneous and complex connective tissue disorder that manifests with low bone density and fragility. More than 15 types of OI have been distinguished on a clinical and molecular basis, but the classical clinical classification previously proposed in Types 1-4 with the recent inclusion of Type 5 appears to be more suitable. The diagnosis is mainly made on clinical and radiographic findings with fractures caused by mild trauma, bowing deformities of long bones, and growth deficiency. Non-skeletal features of the disorder include blue sclerae, hearing loss, decreased pulmonary function, cardiac valvular regurgitation, and muscle weakness.

Case Report: We report on a toddler girl affected by OI Type 1 who suffered from marked muscle weakness as the first initial sign, which led us to follow the diagnostic checklist for hypotonic children. The typical signs of the disorder later became evident and consistent with this diagnosis, including bone fractures and blue sclerae.

Conclusion: Early muscle weakness, previously unreported sign, may be an initial manifestation of OI, to be included in the differential diagnosis of disorders that cause hypotonia in childhood.
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http://dx.doi.org/10.13107/jocr.2250-0685.808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5635191PMC
October 2017

Chromosome 15 structural abnormalities: effect on gene expression and function.

Endocr Connect 2017 Oct;6(7):528-539

Department of Clinical and Experimental MedicineUniversity of Catania, Catania, Italy

Insulin-like growth factor 1 receptor (), mapping on the 15q26.3 chromosome, is required for normal embryonic and postnatal growth. The aim of the present study was to evaluate the gene expression and function in three unrelated patients with chromosome 15 structural abnormalities. We report two male patients with the smallest 15q26.3 chromosome duplication described so far, and a female patient with ring chromosome 15 syndrome. Patient one, with a 568 kb pure duplication, had overgrowth, developmental delay, mental and psychomotor retardation, obesity, cryptorchidism, borderline low testis volume, severe oligoasthenoteratozoospermia and gynecomastia. We found a 1.8-fold increase in the IGF1R mRNA and a 1.3-fold increase in the IGF1R protein expression ( < 0.05). Patient two, with a 650 kb impure duplication, showed overgrowth, developmental delay, mild mental retardation, precocious puberty, low testicular volume and severe oligoasthenoteratozoospermia. The IGF1R mRNA and protein expression was similar to that of the control. Patient three, with a 46,XX r(15) (p10q26.2) karyotype, displayed intrauterine growth retardation, developmental delay, mental and psychomotor retardation. We found a <0.5-fold decrease in the IGF1R mRNA expression and an undetectable IGF1R activity. After reviewing the previously 96 published cases of chromosome 15q duplication, we found that neurological disorders, congenital cardiac defects, typical facial traits and gonadal abnormalities are the prominent features in patients with chromosome 15q duplication. Interestingly, patients with 15q deletion syndrome display similar features. We speculate that both the increased and decreased gene expression may play a role in the etiology of neurological and gonadal disorders.
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http://dx.doi.org/10.1530/EC-17-0158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5597972PMC
October 2017

Maternal Uniparental Disomy 14 (Temple Syndrome) as a Result of a Robertsonian Translocation.

Mol Syndromol 2017 May 16;8(3):131-138. Epub 2017 Feb 16.

Molecular Genetics Unit, Azienda Ospedaliero-Universitaria (AOU) Pisana, Pisa, Italy.

Maternal uniparental disomy of chromosome 14 (upd(14)mat) or Temple syndrome is an imprinting disorder associated with a relatively mild phenotype. The absence of specific congenital malformations makes this condition underdiagnosed in clinical practice. A boy with a de novo robertsonian translocation 45,XY,rob(13;14)(q10;q10) is reported; a CGH/SNP array showed a loss of heterozygosity in 14q11.2q13.1. The final diagnosis of upd(14)mat was made by microsatellite analysis, which showed a combination of heterodisomy and isodisomy for different regions of chromosome 14. Obesity after initial failure to thrive developed, while compulsive eating habits were not present, which was helpful for the clinical differential diagnosis of Prader-Willi syndrome. In addition, the boy presented with many phenotypic features associated with upd(14)mat along with hypoesthesia to pain, previously unreported in this disorder, and bilateral cryptorchidism, also rarely described. These features, as well as other clinical manifestations (i.e., truncal obesity, altered pubertal timing), may suggest a hypothalamic-pituitary involvement. A detailed cytogenetic and molecular characterization of the genomic rearrangement is presented. Early genetic diagnosis permits a specific follow-up of children with upd(14)mat in order to optimize the long-term outcome.
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http://dx.doi.org/10.1159/000456062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5448444PMC
May 2017

Familial 18q12.2 deletion supports the role of RNA-binding protein CELF4 in autism spectrum disorders.

Am J Med Genet A 2017 Jun 13;173(6):1649-1655. Epub 2017 Apr 13.

Department of Clinical and Experimental Medicine, Child Neurology and Psychiatry, University of Catania, Catania, Italy.

Deletion of 18q12.2 is an increasingly recognized condition with a distinct neuropsychiatric phenotype. Twenty-two patients have been described with overlapping neurobehavioral disturbances including developmental delay, intellectual disability of variable degree, seizures, motor coordination disorder, behavioral/emotional disturbances, and autism spectrum disorders. The CUGBP Elav-like family member 4 (CELF4) gene at 18q12.2 encodes a RNA-binding protein that links to RNA subsets involved in pre- and postsynaptic neurotransmission including almost 30% of potential autism-related genes. Haploinsufficiency of CELF4 was associated with an autism or autistic behavior diagnosis in two adult patients with de novo 18q12.2 deletions. We report on a girl and her mildly affected mother with a 275 kb deletion at 18q12.2 involving CELF4 and KIAA1328 whose disruption is not associated with any known disease. The child was diagnosed with syndromic intellectual disability and autism at 6 years of age. Her mother had minor dysmorphisms, mild intellectual disability, and autistic behavior. The deleted region reported in this family is one of the smallest so far reported at 18q12.2. This is also the first full clinical description of maternally inherited CELF4 haploinsufficiency. The present study refines the molecular and neuropsychiatric phenotype associated with 18q12.2 deletion leading to CELF4 haploinsufficiency and provides evidence for a role for CELF4 in brain development and autism spectrum disorders.
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http://dx.doi.org/10.1002/ajmg.a.38205DOI Listing
June 2017

Mutation spectrum of NF1 gene in Italian patients with neurofibromatosis type 1 using Ion Torrent PGM™ platform.

Eur J Med Genet 2017 Feb 9;60(2):93-99. Epub 2016 Nov 9.

Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Palermo, Italy.

Neurofibromatosis type 1 (NF1) is caused by mutations of the NF1 gene and is one of the most common human autosomal dominant disorders. The patient shows different signs on the skin and other organs from early childhood. The best known are six or more café au lait spots, axillary or inguinal freckling, increased risk of developing benign nerve sheath tumours and plexiform neurofibromas. Mutation detection is complex, due to the large gene size, the large variety of mutations and the presence of pseudogenes. Using Ion Torrent PGM™ Platform, 73 mutations were identified in 79 NF1 Italian patients, 51% of which turned out to be novel mutations. Pathogenic status of each variant was classified using "American College of Medical Genetics and Genomics" guidelines criteria, thus enabling the classification of 96% of the variants identified as being pathogenic. The use of Next Generation Sequencing has proven to be effective as for costs, and time for analysis, and it allowed us to identify a patient with NF1 mosaicism. Furthermore, we designed a new approach aimed to quantify the mosaicism percentage using electropherogram of capillary electrophoresis performed on Sanger method.
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http://dx.doi.org/10.1016/j.ejmg.2016.11.001DOI Listing
February 2017

The Koolen-de Vries syndrome: a phenotypic comparison of patients with a 17q21.31 microdeletion versus a KANSL1 sequence variant.

Eur J Hum Genet 2016 May 26;24(5):652-9. Epub 2015 Aug 26.

Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.

The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndrome, is a clinically heterogeneous disorder characterised by (neonatal) hypotonia, developmental delay, moderate intellectual disability, and characteristic facial dysmorphism. Expressive language development is particularly impaired compared with receptive language or motor skills. Other frequently reported features include social and friendly behaviour, epilepsy, musculoskeletal anomalies, congenital heart defects, urogenital malformations, and ectodermal anomalies. The syndrome is caused by a truncating variant in the KAT8 regulatory NSL complex unit 1 (KANSL1) gene or by a 17q21.31 microdeletion encompassing KANSL1. Herein we describe a novel cohort of 45 individuals with KdVS of whom 33 have a 17q21.31 microdeletion and 12 a single-nucleotide variant (SNV) in KANSL1 (19 males, 26 females; age range 7 months to 50 years). We provide guidance about the potential pitfalls in the laboratory testing and emphasise the challenges of KANSL1 variant calling and DNA copy number analysis in the complex 17q21.31 region. Moreover, we present detailed phenotypic information, including neuropsychological features, that contribute to the broad phenotypic spectrum of the syndrome. Comparison of the phenotype of both the microdeletion and SNV patients does not show differences of clinical importance, stressing that haploinsufficiency of KANSL1 is sufficient to cause the full KdVS phenotype.
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http://dx.doi.org/10.1038/ejhg.2015.178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930086PMC
May 2016

Opposite effects on facial morphology due to gene dosage sensitivity.

Hum Genet 2014 Sep 3;133(9):1117-25. Epub 2014 Jun 3.

Molecular Medicine Unit, UCL Institute of Child Health, 30 Guilford St, London, WC1N 1EH, UK,

Sequencing technology is increasingly demonstrating the impact of genomic copy number variation (CNV) on phenotypes. Opposing variation in growth, head size, cognition and behaviour is known to result from deletions and reciprocal duplications of some genomic regions. We propose normative inversion of face shape, opposing difference from a matched norm, as a basis for investigating the effects of gene dosage on craniofacial development. We use dense surface modelling techniques to match any face (or part of a face) to a facial norm of unaffected individuals of matched age, sex and ethnicity and then we reverse the individual's face shape differences from the matched norm to produce the normative inversion. We demonstrate for five genomic regions, 4p16.3, 7q11.23, 11p15, 16p13.3 and 17p11.2, that such inversion for individuals with a duplication or (epi)-mutation produces facial forms remarkably similar to those associated with a deletion or opposite (epi-)mutation of the same region, and vice versa. The ability to visualise and quantify face shape effects of gene dosage is of major benefit for determining whether a CNV is the cause of the phenotype of an individual and for predicting reciprocal consequences. It enables face shape to be used as a relatively simple and inexpensive functional analysis of the gene(s) involved.
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http://dx.doi.org/10.1007/s00439-014-1455-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4148161PMC
September 2014

TBR1 is the candidate gene for intellectual disability in patients with a 2q24.2 interstitial deletion.

Am J Med Genet A 2014 Mar 23;164A(3):828-33. Epub 2014 Jan 23.

Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, (FG), Italy.

Interstitial deletion of 2q24.2 is a rarely described cytogenetic aberration in patients with intellectual disability (ID). Previously reported genotype-phenotype correlation identified a minimum deleted region of 2.65 Mb including 15 genes. Recently, a patient with a de novo 2q24.2 microdeletion of 0.4 Mb encompassing only three genes was described. However, the precise relationship between most deleted genes and the clinical features remains unclear. Here we describe a 12-year-old male patient diagnosed with growth retardation and ID. He also showed microcephaly, right palpebral ptosis, scapular winging, and pectus excavatum. Single nucleotide polymorphisms (SNP) array analysis showed a de novo interstitial deletion of 0.122 Mb at 2q24.2 region harboring only TBR1 (T-box, brain, 1; OMIM: 604616), which encodes a T-box family transcription factor expressed in post-mitotic projection neurons and functionally significant in embryologic corticogenesis. This is the first case of a deletion at 2q24.2 involving only TBR1. This finding narrows the smallest region of overlap (SRO) for deletions in this region and strengthens the previously suggested hypothesis that this gene is a strong candidate for the ID phenotype. The identification of TBR1 as candidate for ID encourages further molecular studies to identify novel mutations to understand the pathogenic effects of its haploinsufficiency. Finally, this report provides a review on 10 2q24.2 microdeletion patients.
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http://dx.doi.org/10.1002/ajmg.a.36363DOI Listing
March 2014

Growth hormone, gender and face shape in Prader-Willi syndrome.

Am J Med Genet A 2013 Oct 5;161A(10):2453-63. Epub 2013 Aug 5.

Molecular Medicine Unit, UCL Institute of Child Health, London, UK.

Prader-Willi syndrome is a neurodevelopmental disorder resulting from the absence of expression of paternally expressed gene(s) in a highly imprinted region of chromosome 15q11-13. The physical phenotype includes evidence of growth retardation due to relative growth hormone deficiency, small hands and feet, a failure of normal secondary sexual development, and a facial appearance including narrow bifrontal diameter, almond-shaped palpebral fissures, narrow nasal root, and thin upper vermilion with downturned corners of the mouth. Anecdotally, the face of individuals with PWS receiving hGH treatment is said to "normalize." We used dense surface modelling and shape signature techniques to analyze 3D photogrammetric images of the faces of 72 affected and 388 unaffected individuals. We confirmed that adults with Prader-Willi syndrome who had never received human growth supplementation displayed known characteristic facial features. Facial growth was significantly reduced in these adults, especially in males. We demonstrated that following human growth hormone (hGH) supplementation, vertical facial growth of affected individuals falls within the normal range. However, lateral and periorbital face shape and nose shape differences in affected children who have received hGH therapy remain sufficiently strong to be significantly discriminating in comparisons with age-sex matched, unaffected individuals. Finally, we produced evidence that age at initiation and length of treatment with hGH do not appear to play a role in normalization or in consistent alteration of the face shape of affected individuals. This is the first study to provide objective shape analysis of craniofacial effects of hGH therapy in Prader-Willi syndrome.
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http://dx.doi.org/10.1002/ajmg.a.36100DOI Listing
October 2013

Craniofacial characteristics of fragile X syndrome in mouse and man.

Eur J Hum Genet 2013 Aug 5;21(8):816-23. Epub 2012 Dec 5.

Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.

For a disorder as common as fragile X syndrome, the most common hereditary form of cognitive impairment, the facial features are relatively ill defined. An elongated face and prominent ears are the most commonly accepted dysmorphic hallmarks. We analysed 3D facial photographs of 51 males and 15 females with full FMR1 mutations and 9 females with a premutation using dense-surface modelling techniques and a new technique that forms a directed graph with normalized face shapes as nodes and edges linking those with closest dysmorphism. In addition to reconfirming known features, we confirmed the occurrence of some at an earlier age than previously recorded. We also identified as yet unrecorded facial characteristics such as reduced facial depth, hypoplasticity of the nasal bone-cartilage interface and narrow mid-facial width exaggerating ear prominence. As no consistent craniofacial abnormalities had been reported in animal models, we analysed micro-CT images of the fragile X mouse model. Results indicated altered dimensions in the mandible and both outer and inner skull, with the latter potentially reflecting differences in neuroanatomy. We extrapolated the mouse results to face shape differences of the human fragile X face.
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http://dx.doi.org/10.1038/ejhg.2012.265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3722676PMC
August 2013
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