[Haplotype Analysis of Oculopharyngeal Muscular Dystrophy (OPMD) Locus in Yakutia].

Oculopharyngeal muscular dystrophy (OPMD) is a hereditary neuromuscular disease with autosomal dominant and rarely with autosomal recessive inheritance types. This study included 50 patients with a clinical diagnosis of OPMD, 23 asymptomatic carriers of the mutation from 45 unrelated families, and 56 healthy relatives, as well as population samples of four ethnic groups of Yakutia: Yakuts, Evens, Evenks, Yukaghirs. It was found that the cause of OPMD development in all investigated families is the same increase in.GCN repeats to 14 copies in the PABPN1 gene. The molecular structure ofthe (GCN)14 mutant allele is (GCG)10(GCA)3GCG. The genetic variability of ten SNPs at the OPMD locus was studied in patient families and population samples. The haplotypes of OPMD were determined by a segregation analysis technique using the EM algorithm in the groups of patients, mutation carriers, and population samples. Only one haplotype of four SNPs (ATCG) linked with the (GCN)14 mutant allele was found in Yakuts and Russian patients and OPMD mutation carriers. Probably, this indicates the accumulation of mutations as a result of the founder effect.

[Population frequency and age of mutation G5741→A in gene NBAS which is a cause of SOPH syndrome in Sakha (Yakutia) Republic].

SOPH syndrome (Short stature with Optic nerve atrophy and Pelger­Huët anomaly syndrome, OMIM#614800) is an autosomal recessive hereditary disease characterized by the following main clinical symptoms: postnatal hypoplasia, proportionately short stature, facial dysmorphism, micromelia of feet and hands, limp and loose skin, optic nerve atrophy, and Pelger­Huët anomaly of neutrophils. For the first time, this disease was described in Yakuts. The molecular-genetic study showed that its cause in Yakuts is mutation G5741→A in gene NBAS. On the basis of disequilibrium analysis for linkage of ten microsatellite markers flanking the NBAS gene with the disease, the haplotype of the founder chromosome was determined. The age of the mutation in Yakutia was estimated to be about 804 ± 140 years. The frequency of heterozygous carriers of mutation G5741→A (R1914H) in gene NBAS was found, which averaged 13 per 1000 healthy Yakuts.

[The clinical-genealogic and molecular-genetic characteristics of oculopharyngeal muscular dystrophy in the Republic of Sakha (Yakutia)].

The clinical-genealogic and molecular-genetic investigation of oculopharyngeal muscular dystrophy (OPMD) in the Republic of Sakha (Yakutia) was performed. It was investigated 33 unrelated Yakut families with 38 patients and 2 russian families with 2 patients and 59 their healthy relatives as well. The high clinical polymorphism of disease was found in patients with OPMD. The mutation in exon 1 of the PABPN1 gene resulting in the expansion of GCG-repeats up to 10 is revealed. Using direct sequencing of the PABPN1 gene in 17 families (16 Yakut, 1 Russian), we identified a type of this mutation as an insertion of 4 GCG-repeats. Frequency of OPMD in the Yakut population is 1:11 680 that is 10-20 times higher comparing to european populations. This is a first report on the patients with OPMD from the Republic of Sakha with diagnosis confirmed by molecular-genetic analysis.