A new de novo frameshift variant has been identified in the CASZ1 gene leading to severe dilated cardiomyopathy. Methods: The proband was analyzed with WES NGS, post-mortem, using dried blood spots on filters. The variant was verified with Sanger sequencing for the proband and her parents. Results: We reported a proband with a new de novo frameshift mutation, c.3781del (p.(Trp1261GlyfsTer29)), in the CASZ1 gene. The clinical presentation was similar to the severe phenotype described in previous studies. Conclusions: In this study, we described a new case with a frameshift mutation in CASZ1 causing a severe phenotype of dilated cardiomyopathy.
Background: Spastic paraplegia type 30 (SPG30) caused by KIF1A mutations was first reported in 2011 and was initially considered a very rare autosomal recessive (AR) form. In the last years, thanks to the development of massive parallel sequencing, SPG30 proved to be a rather common autosomal dominant (AD) form of familial or sporadic spastic paraplegia (SPG),, with a wide range of phenotypes: pure and complicated. The aim of our study is to detect AD SPG30 cases and to examine their molecular and clinical characteristics for the first time in the Russian population. Methods: Clinical, genealogical and molecular methods were used. Molecular methods included massive parallel sequencing (MPS) of custom panel 'spastic paraplegias' with 62 target genes complemented by familial Sanger sequencing. One case was detected by the whole-exome sequencing. Results: AD SPG30 was detected in 10 unrelated families, making it the 3rd (8.4%) most common SPG form in the cohort of 118 families. No AR SPG30 cases were detected. In total, 9 heterozygous KIF1A mutations were detected, with 4 novel and 5 known mutations. All the mutations were located within KIF1A motor domain. Six cases had pure phenotypes, of which 5 were familial, where 2 familial cases demonstrated incomplete penetrance, early onset and slow relatively benign SPG course. All 4 complicated cases were caused by novel mutations without familial history. The phenotypes varied from severe in two patients (e.g. lack of walking, pronounced mental retardation) to relatively mild non-disabling symptoms in two others. Conclusion: AD SPG30 is one of the most common forms of SPG in Russia, the disorder has pronounced clinical variability while pure familial cases represent a significant part.
Введение. Лиcсэнцефалия (ЛЭ) -группа пороков развития коры головного мозга, возникающих в результате нарушения миграции предшественников нейронов к кортикальной пластинке, формирования борозд и извилин в постмиграционном периоде эмбрионального развития. В последние годы в связи с совершенствованием методов молекулярно-генетической диагностики показана значимая роль наследственных факторов в возникновении ЛЭ. Сегодня в группе ЛЭ идентифицировано 13 генетических вариантов, 6 из которых наследуются аутосомно-рецессивно, 5 -аутосомно-доминантно и 2 -сцепленно с Х-хромосомой. В 80 % случаев наследственные ЛЭ обусловлены мутациями в 2 генах: PAFAH1B1, ответственном за возникновение ЛЭ 1-го типа с аутосомно-доминантным типом наследования, и в гене DCX, локализованном на Х-хромосоме. На долю остальных генетических вариантов приходится от 1 до 5 % случаев пороков, сопровождающихся дисгенезией коры головного мозга. В последние годы увеличилось число работ по анализу клинико-генетических характеристик моногенных вариантов ЛЭ. Результаты исследований расширяют представления не только о патогенетических механизмах возникновения данной группы болезней, но и о молекулярных основах нормального формирования структур мозга в эмбриональном периоде. Цель работы -описание клинико-генетических характеристик 3 российских больных с аутосомно-доминантной ЛЭ 3-го типа (OMIM: 611603), обусловленной мутациями в гене TUBA1A. Материалы и методы. Все пациенты находились под наблюдением в консультативно-диагностическом отделении ФГБНУ «МГНЦ им. академика Н. П. Бочкова». Диагноз устанавливался на основании клиники, генеалогического анамнеза, результатов магнитно-резонансной томографии головного мозга, ночного видеоэлектроэнцефалографического мониторинга и секвенирования экзома методом NGS. Валидация выявленных нуклеотидных замен и анализ сегрегации заболевания проводились на основании использования метода прямого автоматического секвенирования по Сэнгеру. Результаты. Проведен анализ клинико-генетических характеристик 3 больных с описанной ранее и впервые выявленными мутациями в гене TUBA1A. Обсуждены возможные эффекты новых миссенс-мутаций в гене на функцию белкового продукта гена. Выводы. Результаты анализа клинико-генетических характеристик наблюдаемых нами больных вносят вклад в изучение полиморфизма клинических проявлений, возникающих в результате мутаций в гене TUBA1A. Подтверждено высказанное ранее предположение о широком спектре пороков развития головного мозга у больных с мутациями в этом гене, что должно учитываться при постановке диагноза.
Hearing loss is one of the most genetically heterogeneous disorders known. Over 120 genes are reportedly associated with non-syndromic hearing loss (NSHL). To date, in Russia, there have been relatively few studies that apply massive parallel sequencing (MPS) methods to elucidate the genetic factors underlying non-GJB2-related hearing loss cases. The current study is intended to provide an understanding of the mutation spectrum in non-GJB2-related hearing loss in a cohort of Russian sensorineural NSHL patients and establish the best diagnostic algorithm. Genetic testing using an MPS panel, which included 33 NSHL and syndromic hearing loss (SHL) genes that might be misdiagnosed as NSHL genes, was completed on 226 sequentially accrued and unrelated patients. As a result, the molecular basis of deafness was found in 21% of the non-GJB2 NSHL cases. The total contribution pathogenic, and likely pathogenic, variants in the genes studied among all hereditary NSHL Russian patients was 12%. STRC pathogenic and likely pathogenic, variants accounted for 30% of diagnoses in GJB2-negative patients, providing the most common diagnosis. The majority of causative mutations in STRC involved large copy number variants (CNVs) (80%). Among the point mutations, the most common were c.11864G>A (p.Trp3955*) in the USH2A gene, c.2171_2174delTTTG (p.Val724Glyfs*6) in the STRC gene, and c.107A>C (p.His36Pro) and c.1001G>T (p.Gly334Val) in the SLC26A4 gene. Pathogenic variants in genes involved in SHL accounted for almost half of the cases with an established molecular genetic diagnosis, which were 10% of the total cohort of patients with non-GJB2-related hearing loss.
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