Spectrum of Genes for Non-GJB2-Related Non-Syndromic Hearing Loss in the Russian Population Revealed by a Targeted Deafness Gene Panel

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

Complex Diagnostics of Non-Specific Intellectual Developmental Disorder

Intellectual development disorder (IDD) is characterized by a general deficit in intellectual and adaptive functioning. In recent years, there has been a growing interest in studying the genetic structure of IDD. Of particular difficulty are patients with non-specific IDD, for whom it is impossible to establish a clinical diagnosis without complex genetic diagnostics. We examined 198 patients with non-specific IDD from 171 families using whole-exome sequencing and chromosome microarray analysis. Hereditary forms of IDD account for at least 35.7% of non-specific IDD, of which 26.9% are monogenic forms. Variants in the genes associated with the BAF (SWI/SNF) complex were the most frequently identified. We were unable to identify phenotypic features that would allow differential diagnosis of monogenic and microstructural chromosomal rearrangements in non-specific IDD at the stage of clinical examination, but due to its higher efficiency, exome sequencing should be the diagnostic method of the highest priority study after the standard examination of patients with NIDD in Russia

Мышечная дистрофия Дюшенна: современные подходы к ведению и лечению пациентов

Duchenne muscular dystrophy is one of the most common forms of childhood muscular dystrophies. Its incidence is 1 in 3.5–6 thousand newborn boys according to various sources. The disease is caused by the mutation in the DMD gene coding the dystrophin protein, it leads to the dystrophin absence or malfunction. The disease is characterized by proximal muscle weakness and gastrocnemius muscles pseudohypertrophy. In average, patients lose the ability to walk by themselves by the age of 11 and become nonambulatory. The authors have present modern epidemiological data and etiopathogenesis features of Duchenne muscular dystrophy, and have described clinical signs of different disease stages. The algorithm and key points of differential diagnosis are indicated. Special attention was given to the patients’ management: pathogenetic treatment and rehabilitation of pediatric patients.Мышечная дистрофия Дюшенна — одна из наиболее частых форм мышечных дистрофий детского возраста. По разным источникам, заболеваемость миодистрофией Дюшенна оценивается как 1 на 3,5–6 тыс. новорожденных мальчиков. В основе заболевания лежит мутация гена DMD, кодирующего белок дистрофин, приводящая к отсутствию или недостаточной функции дистрофина. Заболевание характеризуется слабостью проксимальных и псевдогипертрофией икроножных мышц, и в среднем к 11 годам пациенты теряют возможность самостоятельно передвигаться и становятся неамбулаторными больными. Авторами представлены современные эпидемиологические данные и особенности этиопатогенеза мышечной дистрофии Дюшенна, описаны клинические характеристики разных стадий болезни. Подробно представлен алгоритм и указаны ключевые этапы дифференциально-диагностического поиска. Особое внимание уделено вопросам лечения пациентов, в том числе патогенетическому лечению, реабилитации пациентов детского возраста

Клинические рекомендации по ведению детей с дефицитом лизосомной кислой липазы

Lysosomal acid lipase deficiency is s a rare hereditary enzymopathy. The article presents epidemiological data and features of etiopathogenesis of two phenotypic forms of lysosomal acid lipase deficiency — Wolman disease and cholesterol ester storage disease. Special attention has been given to the key issues of differential diagnostic search, clinical guidelines based on the principles of evidence-based medicine have been given.Дефицит лизосомной кислой липазы — редкая наследственная ферментопатия. В статье представлены эпидемиологические данные и особенности этиопатогенеза двух фенотипических форм дефицита лизосомной кислой липазы — болезни Вольмана и болезни накопления эфиров холестерина. Подробно описаны клинические характеристики быстропрогрессирующей формы и медленно развивающейся болезни накопления эфиров холестерина. Особое внимание уделено ключевым вопросам дифференциально-диагностического поиска, приведены рекомендации по лечению, основанные на принципах доказательной медицины