Phenotypic and Genotypic Analysis of Hereditary Ataxia Patients in Sakarya City, Turkey

Conclusion: Hereditary ataxias are rare neurodegenerative disorders. Large genetic pool, ethnic and local differences complicate diagnosing even further. Our study contributes to the literature by reflecting phenotypic and genotypic characteristics of hereditary SCA patients in our region and reporting rare hereditary ataxia genotypes

Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

Dentatorubral pallidoluysian atrophy in a Turkish family

Dentatorubral pallidoluysian atrophy is a neurodegenerative disease that generally presents in adulthood. Although rare, it can be observed in childhood due to extreme expansion of the triplet repeat size during spermatogenesis. The diagnosis in childhood is very difficult in the absence of family history. Here we describe a 12-year-old girl with dentatorubral pallidoluysian atrophy who presented with progressive myoclonic epilepsy and ataxia. Family history exhibited similarly affected cases on the paternal side. Molecular testing for dentatorubral pallidoluysian atrophy revealed abnormal "cytosine-adenine-guanosine" expansion in the atrophin-1 gene

Association of a synonymous SCN1B variant affecting splicing efficiency with Benign Familial Infantile Epilepsy (BFIE)

Benign Familial Infantile Epilepsy (BFIE) is clinically characterized by clusters of brief partial seizures progressing to secondarily generalized seizures with onset at the age of 3-7 months and with favorable outcome. PRRT2 mutations are the most common cause of BFIE, and found in about 80% of BFIE families. In this study, we analyzed a large multiplex BFIE family by linkage and whole exome sequencing (WES) analyses. Genome-wide linkage analysis revealed significant evidence for linkage in the chromosomal region 19p12-q13 (LOD score 3.48). Mutation screening of positional candidate genes identified a synonymous SCN1B variant (c.492T>C, p.Tyr164Tyr) affecting splicing by the removal of a splicing silencer sequence, shown by in silico analysis, as the most likely causative mutation. In addition, the PRRT2 frameshift mutation (c.649dupC/p.Arg217Profs*8) was observed, showing incomplete, but high segregation with the phenotype. In vitro splicing assay of SCN1B expression confirmed the in silico findings showing a splicing imbalance between wild type and mutant exons. Herein, the involvement of the SCN1B gene in the etiology of BFIE, contributing to the disease phenotype as a modifier or part of an oligogenic predisposition, is shown for the first time. (C) 2017 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved

FBX07-R498X mutation: Phenotypic variability from chorea to early onset parkinsonism within a family

Objective: FBXO7 mutations (PARK 15), first reported in 2008, are among the monogenic causes of early-onset parkinsonism. Classically, PARK 15 was suggested to correspond to previously described pallido-pyramidal syndrome. Here, we report clinical and genetic findings in a unique family of Kurdish origin with an FBXO7 mutation and presenting with diverse clinical phenotypes

SCN1A gene sequencing in 46 Turkish epilepsy patients disclosed 12 novel mutations

Purpose: The SCN1A gene is one of the most commonly mutated human epilepsy genes associated with a spectrum of phenotypes with variable degrees of severity. Despite over 1200 distinct mutations reported, it is still hard to draw clear genotype phenotype relationships, since genetic and environmental modifiers contribute to the development of a particular disease caused by an SCN1A mutation. We aimed to initiate mutational screening of the SCN1A gene in Turkey and advance further our understanding of the relationship between the SCN1A sequence alterations and disease phenotypes such as GEFS+, DS and related epileptic encephalopathies

The distinct genetic pattern of ALS in Turkey and novel mutations

The frequency of amyotrophic lateral sclerosis (ALS) mutations has been extensively investigated in several populations; however, a systematic analysis in Turkish cases has not been reported so far. In this study, we screened 477 ALS patients for mutations, including 116 familial ALS patients from 82 families and 361 sporadic ALS (sALS) cases. Patients were genotyped for C9orf72 (18.3%), SOD1 (12.2%), FUS (5%), TARDBP (3.7%), and UBQLN2 (2.4%) gene mutations, which together account for approximately 40% of familial ALS in Turkey. No SOD1 mutations were detected in sALS patients; however, C9orf72 (3.1%) and UBQLN2 (0.6%) explained 3.7% of sALS in the population. Exome sequencing revealed mutations in OPTN, SPG11, DJ1, PLEKHG5, SYNE1, TRPM7, and SQSTM1 genes, many of them novel. The spectrum of mutations reflect both the distinct genetic background and the heterogeneous nature of the Turkish ALS population. (C) 2015 Elsevier Inc. All rights reserved

The Distinct Genetic Pattern of ALS in Turkey and Novel Mutations

The frequency of amyotrophic lateral sclerosis (ALS) mutations has been extensively investigated in several populations; however, a systematic analysis in Turkish cases has not been reported so far. In this study, we screened 477 ALS patients for mutations, including 116 familial ALS patients from 82 families and 361 sporadic ALS (sALS) cases. Patients were genotyped for C9orf72 (18.3%), SOD1 (12.2%), FUS (5%), TARDBP (3.7%), and UBQLN2 (2.4%) gene mutations, which together account for approximately 40% of familial ALS in Turkey. No SOD1 mutations were detected in sALS patients; however, C9orf72 (3.1%) and UBQLN2 (0.6%) explained 3.7% of sALS in the population. Exome sequencing revealed mutations in OPTN, SPG11, DJ1, PLEKHG5, SYNE1, TRPM7, and SQSTM1 genes, many of them novel. The spectrum of mutations reflect both the distinct genetic background and the heterogeneous nature of the Turkish ALS population. (C) 2015 Elsevier Inc. All rights reserved.Wo

The Complex Genetic Landscape of Hereditary Ataxias in Turkey and Implications in Clinical Practice

Background The genetic and epidemiological features of hereditary ataxias have been reported in several populations; however, Turkey is still unexplored. Due to high consanguinity, recessive ataxias are more common in Turkey than in Western European populations