Hearing loss is a genetically heterogeneous sensory defect, and the frequent causes are biallelic pathogenic variants in the GJB2 gene. However, patients carrying only one heterozygous pathogenic (monoallelic) GJB2 variant represent a long-lasting diagnostic problem. Interestingly, previous results showed that individuals with a heterozygous pathogenic GJB2 variant are two times more prevalent among those with hearing loss compared to normal-hearing individuals. This excess among patients led us to hypothesize that there could be another pathogenic variant in the GJB2 region/DFNB1 locus. A hitherto undiscovered variant could, in part, explain the cause of hearing loss in patients and would mean reclassifying them as patients with GJB2 biallelic pathogenic variants. In order to detect an unknown causal variant, we examined 28 patients using NGS with probes that continuously cover the 0.4 Mb in the DFNB1 region. An additional 49 patients were examined by WES to uncover only carriers. We did not reveal a second pathogenic variant in the DFNB1 region. However, in 19% of the WES-examined patients, the cause of hearing loss was found to be in genes other than the GJB2. We present evidence to show that a substantial number of patients are carriers of the GJB2 pathogenic variant, albeit only by chance.

• MeSH
• frekvence genu MeSH
• heterozygot MeSH
• konexin 26 genetika   MeSH
• lidé MeSH
• mutace MeSH
• percepční nedoslýchavost genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Non-syndromic autosomal recessive hearing loss is an extremely heterogeneous disease caused by mutations in more than 80 genes. We examined Czech patients with early/prelingual non-syndromic, presumably genetic hearing loss (NSHL) without known cause after GJB2 gene testing. Four hundred and twenty-one unrelated patients were examined for STRC gene deletions with quantitative comparative fluorescent PCR (QCF PCR), 197 unrelated patients with next-generation sequencing by custom-designed NSHL gene panels and 19 patients with whole-exome sequencing (WES). Combining all methods, we discovered the cause of the disease in 54 patients. The most frequent type of NSHL was DFNB16 (STRC), which was detected in 22 patients, almost half of the clarified patients. Other biallelic pathogenic mutations were detected in the genes: MYO15A, LOXHD1, TMPRSS3 (each gene was responsible for five clarified patients, CDH23 (four clarified patients), OTOG and OTOF (each gene was responsible for two clarified patients). Other genes (AIFM1, CABP2, DIAPH1, PTPRQ, RDX, SLC26A4, TBC1D24, TECTA, TMC1) that explained the cause of hearing impairment were further detected in only one patient for each gene. STRC gene mutations, mainly deletions remain the most frequent NSHL cause after mutations in the GJB2.

• MeSH
• dítě MeSH
• dospělí MeSH
• genetická predispozice k nemoci MeSH
• hluchota embryologie   genetika   patologie   MeSH
• kadheriny genetika   MeSH
• konexin 26 genetika   MeSH
• lidé MeSH
• membránové glykoproteiny genetika   MeSH
• membránové proteiny genetika   MeSH
• mezibuněčné signální peptidy a proteiny genetika   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• myosiny genetika   MeSH
• nádorové proteiny genetika   MeSH
• nedoslýchavost epidemiologie   genetika   patologie   MeSH
• sekvenování exomu MeSH
• serinové endopeptidasy genetika   MeSH
• transportní proteiny genetika   MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

INTRODUCTION: Hearing loss is the most frequent sensory disorder and is genetically extremely heterogeneous. By far the most frequent cause of nonsyndromic autosomal recessive hearing loss (AR-NSHL) are biallelic pathogenic mutations in the GJB2 gene causing DFNB1. The worldwide search for the second most common type of AR-NSHL took almost two decades. Recently reported alterations (mostly deletions) of the STRC gene, also named DFNB16, seem to be the second most frequent cause of AR-NSHL. Genetic testing of STRC is very challenging due to the highly homologous pseudogene. Anecdotal evidence from single patients shows that STRC mutations have their typical audiological findings and patients usually have moderate hearing loss. The aim of this study is to discover if audiological findings in patients with biallelic pathogenic mutations affecting STRC have the characteristic features and shape of audiological curves and if there are genotype/phenotype correlations in relation to various types of STRC mutations. METHODS: Eleven hearing loss patients with pathogenic mutations on both alleles of the STRC gene were detected during routine genetic examination of AR-NSHL patients. Audiological examination consisted of pure tone audiometry, stapedial reflexes, tympanometry and otoacoustic emission tests. RESULTS: The threshold of pure tone average (PTA) was 46 dB and otoacoustic emissions were not detectable in these DFNB16 patients. All patients were without vestibular irritation or asymmetry. CONCLUSION: Moderate sensorineural hearing loss is typical for DFNB16-associated hearing loss and there are no significant differences in audiological phenotypes among different types of mutations affecting STRC.

• MeSH
• alely MeSH
• audiometrie MeSH
• dítě MeSH
• dospělí MeSH
• genetické asociační studie MeSH
• hluchota genetika   MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• konexiny genetika   MeSH
• lidé MeSH
• membránové proteiny genetika   MeSH
• mezibuněčné signální peptidy a proteiny genetika   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• percepční nedoslýchavost diagnóza   genetika   MeSH
• polymerázová řetězová reakce MeSH
• sekvenční delece genetika   MeSH
• sluchové testy MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

INTRODUCTION: Hearing loss (HL) is the most common sensory deficit in humans. HL is an extremely heterogeneous condition presenting most frequently as a nonsyndromic (NS) condition inherited in an autosomal recessive (AR) pattern, termed DFNB. Mutations affecting the STRC gene cause DFNB type 16. Various types of mutations within the STRC gene have been reported from the U.S. and German populations, but no information about the relative contribution of STRC mutations to NSHL-AR among Czech patients is available. METHODS AND PATIENTS: Two hundred and eighty-eight patients with prelingual NSHL, either sporadic (n = 207) or AR (n = 81), who had been previously tested negative for the mutations affecting the GJB2 gene, were included in the study. These patients were tested for STRC mutations by a quantitative comparative fluorescent polymerase chain reaction (QF-PCR) assay. In addition, 31 of the 81 NSHL-AR patients were analyzed by massively parallel sequencing using one of two different gene panels: 23 patients were analyzed by multiplex-ligation probe amplification (MLPA); and 9 patients by SNP microarrays. RESULTS: Causal mutations affecting the STRC gene (including copy number variations [CNVs] and point mutations) were found in 5.5% of all patients and 13.6% of the 81 patients in the subgroup with NSHL-AR. CONCLUSION: Our results provide strong evidence that STRC gene mutations are an important cause of NSHL-AR in Czech HL patients and are probably the second most common cause of DFNB. Large CNVs were more frequent than point mutations and it is reasonable to test them first by a QF-PCR method-a simple, accessible, and efficient tool for STRC CNV detection, which can be combined by MLPA.

• MeSH
• lidé MeSH
• membránové proteiny genetika   MeSH
• mutace * MeSH
• nedoslýchavost genetika   MeSH
• polymerázová řetězová reakce MeSH
• sekvenční delece MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

OBJECTIVE: To highlight importance of detailed ultrasound examination in fetuses with known normal karyotype (and micro-array result) from CVS. In case of markedly abnormal ultrasound result repeated karyotyping by amniocentesis should be considered. Sample should be analyzed by routine cytogenetic techniques, however also micro-array and targeted FISH should be added in order to achieve most accurate diagnosis. CASE REPORT: We report prenatal diagnosis of Pallister-Killian Syndrome (PKS) at 18 gestational weeks. The mother asked us for second opinion scan in our centre due to finding of seven soft markers of chromosomal defects in fetus with normal CVS result. Our examination revealed asymmetrical fetal growth, normohydramnion, spastic fetal movements and several abnormalities: nuchal edema, mild bilateral hydronephrosis, omphalocoele and facial anomalies. We asked for targeted genetic analysis for PKS. Amniocentesis with repeated genetic analysis confirmed PKS (80% mosaicism of tetrasomy 12p). CONCLUSION: Diagnosis of PKS led mother to terminate pregnancy.

• MeSH
• amniocentéza MeSH
• chromozomální poruchy diagnóza   embryologie   genetika   MeSH
• dospělí MeSH
• druhý trimestr těhotenství MeSH
• genetické testování metody   MeSH
• gestační stáří MeSH
• lidé MeSH
• lidské chromozomy, pár 12 genetika   MeSH
• mozaicismus MeSH
• odběr choriových klků * MeSH
• prenatální diagnóza metody   MeSH
• těhotenství MeSH
• ultrasonografie prenatální * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

We observed bilateral cataracts on second trimester ultrasound, in two consecutive pregnancies, with no other structural defects detected. The parents were unrelated and had no family history for the disease. The first pregnancy was terminated in week 22. Copy number variation analysis revealed, in both the aborted fetus and the mother, a 495 kb duplication at 22q11.23 encompassing CRYBB3 and CRYBB2, and not present in variation databases. In the second pregnancy, lens hyperechogenicity was detected by ultrasound at week 13 and 4 days. The identical duplication at 22q11.23 was found in the fetus and considered as possibly pathogenic. At weeks 22 and 30, smaller orbit measurements were elucidated on ultrasound, raising concerns as to the underlying molecular genetic cause, necessitating further investigation. Whole-exome sequencing, using DNA of the first fetus, was performed shortly after the birth of a male child, and two truncating RAB3GAP1 mutations were detected: c.538G>T; p. (Glu180*) and c.943C>T; p. (Arg315*). Neither mutation has been previously reported to be disease-causing; however, evaluation in the context of previously published literature indicated their deleterious nature, implying a clinical diagnosis of Warburg micro syndrome or Martsolf syndrome. Sanger sequencing confirmed segregation of the two mutations within the family, consistent with autosomal recessive inheritance. The child born from the second pregnancy showed features typical of Warburg micro syndrome, with the exception of microcephaly, at age 31 months. © 2016 Wiley Periodicals, Inc.

• MeSH
• atrofie optického nervu diagnóza   genetika   patofyziologie   MeSH
• beta-krystaliny - řetězec B genetika   MeSH
• exony genetika   MeSH
• hypogonadismus diagnóza   genetika   patofyziologie   MeSH
• katarakta vrozené   diagnóza   genetika   patofyziologie   MeSH
• kojenec MeSH
• lidé MeSH
• mentální retardace diagnóza   genetika   patofyziologie   MeSH
• mikrocefalie diagnóza   genetika   patofyziologie   MeSH
• mnohočetné abnormality diagnóza   genetika   patofyziologie   MeSH
• mutace MeSH
• novorozenec MeSH
• potracený plod patofyziologie   MeSH
• rab3 proteiny vázající GTP genetika   MeSH
• rodokmen MeSH
• rohovka abnormality   patofyziologie   MeSH
• sekvenční analýza DNA MeSH
• těhotenství MeSH
• ultrasonografie prenatální MeSH
• variabilita počtu kopií segmentů DNA genetika   MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• cytogenetické vyšetření MeSH
• dospělí MeSH
• lidé MeSH
• lidské chromozomy, pár 16 * genetika   MeSH
• mozaicismus * MeSH
• potrat eugenický MeSH
• prenatální diagnóza MeSH
• těhotenství MeSH
• trizomie * diagnóza   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• abstrakt z konference MeSH
• kazuistiky MeSH

Cíl studie: Metoda SNP array (využívající k diagnostice polymorfismy v 1 nukleotidu – single nucleotide polymorphism) umožňuje odhalit v karyotypu nedetekovatelné submikroskopické změny (mikrodelece, mikroduplikace), jež mohou mít kauzální souvislost s patologickým ultrazvukovým nálezem u plodu. V článku je stručně popsán princip, výhody, nevýhody a možnosti použití metody SNP array v prenatální diagnostice. Jsou prezentovány zkušenosti za 10 měsíců používání této metody v prenatální diagnostice. Typ studie: Prospektivní studie. Pracoviště: Gennet, Praha. Metodika: Vyšetření SNP array bylo v období duben 2010 až leden 2011 provedeno u 110 vzorků DNA získané z kultivovaných nebo nekultivovaných buněk plodů po biopsii choria (CVS, n=14), amniocentéze (AMC, n=88), kordocentéze (n=1) a z tkáně z abortů (n=7). Vyšetření byla indikována na základě patologického nálezu na ultrazvuku s normálním karyotypem plodu, případně k dořešení patologického cytogenetického nálezu vzniklého de novo. Zpracování DNA pro chip Illumina InfiniumHD HumanCytoSNP-12v2.1, jeho příprava a skenování byly provedeny podle standardních protokolů firmy Illumina. Data byla analyzována pomocí softwaru Illumina KaryoStudio a GenomeStudio. Výsledky: Metodou SNP array bylo úspěšně vyhodnoceno 108 vzorků (neúspěch vyšetření byl pouze ve 2 případech, 1,8 %). Odchylky od normálního profilu (CNV-Copy Number Variation) byly zachyceny u 29 případů (29/108 = 27 %), z nichž 16 bylo klinicky významných (16/108=15 %). Jako pravděpodobně nepatogenní byly CNV u 8 případů a u 5 případů nebyl zatím původ nalezené CNV ověřen u rodičů. Po odečtení případů ověřujících de novo patologii v karyotypu plodu byla klinicky významná CNV nalezena v 9 případech (9/94 = 10 %). Nález klinicky významné CNV byl nejčastěji v kategorii ultrazvukových nálezů srdečních vad, vad centrálního nervového systému (CNS) a mnohočetných anomálií. Ve všech 14 případech de novo chromozomální přestavby v karyotypu byla jasně specifikována závažnost přestavby (patologie u 7/14 = 50 %). Závěr: Výsledky studie ukazují, že vedle jednoznačného přínosu při posuzování patogenity de novo chromozomálních aberací prokazuje SNP array i jednoznačný přínos pro záchyt dosud skrytých submikroskopických změn.

Objectives: SNP array (array method using Single Nucleotide Polymorphisms) enables to detect cytogenetically undetectable submicroscopic alterations (microdeletions, microduplications), which could be also causative for ultrasonographic anomalies of fetus. This article describes the principle, advantages, disadvantages and application possibilities of the SNP array method in prenatal diagnosis. The ten month experience with SNP array use in prenatal diagnosis is presented. Design: Prospective study. Settings: Gennet, Prague. Material and methods: During the period from April 2010 to January 2011 we performed 110 SNP array analyses of fetal DNA: 14 chorionic villi samples (CVS), 88 amniotic fluid samples (AMC), 1 cord blood sample and 7 miscarriage samples. Laboratory tests were carried out on DNA from both cultured and uncultured fetal cells. Examinations were performed in fetuses with sonographic abnormal findings having normal karyotype. In addition 14 fetal cytogenetic abnormalities were solved. SNP array analysis was performed using Illumina InfiniumHD HumanCytoSNP-12 chip. All data were analysed by Illumina KaryoStudio and GenomeStudio software. Results: SNP array analysis was performed in 108 fetuses (only 2 examination failures, 1.8%). In total, we detected CNV (copy number variation) in 29 samples (29/108 = 27%). 15% (16/108) of fetuses with abnormal ultrasound findings were found to carry clinically relevant CNV. Probably benign CNVs were found in 8 samples (8/108 = 7%) and in additional 5 CNVs parental samples have not been analysed yet. Excluding karyotypically abnormal cases clinically relevant CNVs were found in 10% of fetuses (9/94). In all cases with de novo chromosomal aberration the clinical relevancy was clarified (imbalances in 50%). Conclusion: Our data suggest that SNP array analysis is a relevant and useful technique in prenatal diagnosis.

• Klíčová slova
• ultrazvuková diagnostika,
• MeSH
• jednonukleotidový polymorfismus MeSH
• lidé MeSH
• prenatální diagnóza MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• těhotenství MeSH
• ultrasonografie prenatální MeSH
• vrozené vady diagnóza   genetika   ultrasonografie   MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH

• Publikační typ
• abstrakt z konference MeSH

Mutations in SLC26A4 cause Pendred syndrome (PS) - hearing loss with goitre - or DFNB4 - non-syndromic hearing loss (NSHL) with inner ear abnormalities such as Enlarged Vestibular Aqueduct (EVA) or Mondini Dysplasia (MD). We tested 303 unrelated Czech patients with early hearing loss (298 with NSHL and 5 with PS), all GJB2-negative, for SLC26A4 mutations and evaluated their clinical and radiological phenotype. Among 115 available HRCT/MRI scans we detected three MD (2.6%), three Mondini-like affections (2.6%), 16 EVA (13 bilateral - 19.2% and 15.6% respectively) and 61 EVA/MD-negative scans (73.4%). We found mutation(s) in 26 patients (8.6%) and biallelic mutations in eight patients (2.7%) out of 303 tested. In 18 of 26 (69%) patients, no second mutation could be detected even using MLPA. The spectrum of SLC26A4 mutations in Czech patients is broad without any prevalent mutation. We detected 21 different mutations (four novel). The most frequent mutations were p.Val138Phe and p.Leu445Trp (18% and 8.9% of pathogenic alleles respectively). Among 13 patients with bilateral EVA, six patients (50%) carry biallelic mutations. In EVA -negative patients no biallelic mutations were found but 4.9% had monoallelic mutations. SLC26A4 mutations are present mostly in patients with EVA/MD and/or progressive HL and those with affected siblings.

• MeSH
• aquaeductus vestibularis patologie   MeSH
• fenotyp MeSH
• lidé MeSH
• membránové transportní proteiny genetika   MeSH
• mutace MeSH
• percepční nedoslýchavost genetika   patologie   MeSH
• prevalence MeSH
• syndrom MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH