Vol 18, No 2 (2019)
ORIGINAL RESEARCH
24-34 1055
Abstract
Relevance. The study of the gene polymorphism of the system biotransformation of xenobiotics, which are associated with a number of multifactorial diseases, is an important area of modern medical genetic research. The aim and tasks are to reveal ethnic features in the distribution of polymorphic variants of genes GSTM1, GSTT1 and GSTP1 among Buryats, Teleuts and Russians of Eastern Siberia. Materials and methods. The samples of Eastern (N=139) and Western (N=284) Buryats, métis Western Buryats with Russians (N=47), Teleuts (N=115) and Russians of East Siberia (N=122) are studied. Detection of GSTM1 0/0 and GSTT1 0/0 was carried out through multiplex real-time PCR. Genotyping of GSTP1 was performed using TaqMan real-time PCR. Results. The occurrence of GSTM1 0/0 among Eastern and Western Buryats is 37.7% and 57.7% respectively (51.4% for the total sample of Buryats), among Russians - 42.6%. Significantly lower frequency is shown in Teleuts-17.4%. The frequency of GSTT1 0/0 in Eastern and Western Buryats is 40.8% and 27.6% respectively. It is significantly lower in Russians - 18%, in Teleuts - 24.8%. Mestis shows intermediate frequencies of GSTM1 0/0 and GSTТ1 0/0. GSTP1 1405G is found among Eastern and Western Buryats with 27.7% and 19.2% frequency, respectively, in Russians - 31.8%, Teleuts - 24.8%. The difference of Russians with Western Buryats is statistically significant. The frequencies of GSTP1 2285T among Eastern (4.9%), Western (1.8%) Buryats and Teleuts (2.2%) are lower than frequency among Russians (8.3%). The difference between Russians and Western Buryats with Teleuts is statistically significant. Summary. There are increased frequencies of GSTM1 0/0 and GSTT1 0/0 in the total cohort of Buryats in comparison with Teleuts and Russians. According to the literature data, these genotypes are associated with multi-factorial diseases. In both samples of Buryats, there is a statistically significantly increased frequency of the combined genotype resulting in the absence of enzyme activity. At the same time, there is a statistically significantly increased frequency of individuals with a genotypic combination GSTM1 +GSTT1 + responsible for normal enzymatic activity in the sample of Teleuts. There are reduced frequencies of risk-alleles GSTP1 1405G and 2285T among Buryats and Teleuts in comparison with Russians. Metisation changes the frequency of risk alleles. Significant differences in the frequencies of GSTM1, GSTT1 and GSTP1 within the Buryat ethnic group may indicate its genetic heterogeneity.
35-41 953
Abstract
The aim of study was to evaluate X-chromosome mosaicism in health fertile women from different age groups. We found physiological low-level gonosomal mosaicism in peripheral blood lymphocytes with a clear trend in increased proportion of X-aneuploidic cells associated with the increasing age to 1.83%, 2.23% and 5.88% for 20-29, 30-39 and 40-49 years, respectively. The buccal smear also exhibited physiological pattern of a low-level X-chromosome mosaicism, however, the level of gonosomal mosaicism with no statistically significant difference between groups, average level was 4.01%. The obtained data allow to developed diagnostic protocol of low-level X-chromosome mosaicism in fertile women.
INFORMATION
CLINICAL CASE
42-48 920
Abstract
Background. Hereditary spastic paraplegias (HSPs) are a large group of neurodegenerative disorders characterized by progressive lower limbs spasticity and weakness caused by a retrograde axonal degeneration of the corticospinal tracts. The considerable and constantly increasing number of HSP-associated genes (more than 80 different loci with 60 corresponding spastic paraplegia genes) complicates the diagnosis in every particular case, especially with a single reported occurrence like the autosomal recessive spastic paraplegia 61 (SPG61, OMIM: 615685). However, new sequencing methods allow to accelerate the process and find the molecular cause of the disease much more reliably, especially in families with rare HSPs. Aims. To describe a rare complicated early-onset HSP (SPG61) in a Dargin consanguineous family and find out its molecular genetical cause. Materials and methods: personal and family history analysis, neurological examination, electroencephalography, brain MRI, blood DNA extraction, whole exome sequencing (WES), WES data analysis, Sanger sequencing. Results. During a session of whole-exome sequencing and analysis, a new homozygous variant c.[92T>C];[92T>C] (p.[(Leu31Pro)];[(Leu31Pro)], NM_015161.1) has been discovered in exon 2 of the ARL6IP1 gene, which makes it the second variant found in this gene worldwide and the first one in Russia. Sanger sequencing of the patients’ and parents’ DNA confirmed the p.(Leu31Pro) variant status (homozygous in both patients and heterozygous in both parents) and its segregation with the disease status. Here we describe the clinical findings of the disease in this family and a clinical data comparison for two families with variants in the ARL6IP1 gene (described previously and studied in our laboratory). Conclusions. Our research broadens the diversity of symptoms associated with ARL6IP1 gene mutations. The discovered variant expands the causative mutation spectrum of complicated early-onset HSPs.
ОРГАНИЗАЦИОННО-МЕТОДИЧЕСКИЕ АСПЕКТЫ
O. P. Ryzhkova,
O. L. Kardymon,
E. B. Prohorchuk,
F. A. Konovalov,
A. B. Maslennikov,
V. A. Stepanov,
A. A. Afanasyev,
E. V. Zaklyazminskaya,
D. V. Rebrikov,
K. V. Savostianov,
A. S. Glotov,
A. A. Kostareva,
A. E. Pavlov,
M. V. Golubenko,
A. V. Polyakov,
S. I. Kutsev
3-23 5227
Abstract
This is a second version of guidelines for the interpretation of massive parallel sequencing (MPS) variants. First version was published in Medical Genetics journal in 2017. They were based on ACMG, CAP, ESHG and FDA guidelines and recommendations. Leading authorities on medical genetics and bioinformatics updated and finalized them. First version of guidelines was presented and discussed on all Russian conference «NGS in medical genetics» and all Russian conference «New technologies for diagnosing hereditary diseases». All members of these conferences and members of Russian Society of Medical Genetics could introduce amendments and give comments. Current version include reviewed notes and comments.
ISSN 2073-7998 (Print)