To perform a clinical-genealogical and molecular genetic analysis of X-linked spinal-bulbar amyotrophy (Kennedy's disease) in the Sakha Republic (Yakutia).
Six patients, aged from 30 to 60 years, from 4 unrelated Yakut families registered in the Republican genetics registry of hereditary and congenital abnormalities of the Sakha Republic were studied. The average age of onset was 45.1±4.4 years. A clinical-genealogical and molecular genetic methods were used.
The prevalence of spinal-bulbar amyotrophy Kennedy in the Republic of Sakha (Yakutia) is 1.3 per 100 thousand, among Yakut men is 2.8 per 100 thousand. Clinical manifestations of the disease in the patients included in the study were similar to those described previously in the literature. Patients underwent molecular genetic diagnosis in exon 1 of the androgen receptor (AR) gene. All of them carried the allele with more than 38 CAG repeats. There was an inverse correlation between the age at disease onset and the number of CAG-repeats. A method of DNA diagnosis of Kennedy's disease with visualization on an agarose gel has been introduced in genetic testing.
The 32-bp deletion (CCR5del32 mutation) in the CCR5 (chemokine (C-C motif) receptor 5) gene, encoding CCR5 chemokine receptor, is one of the factors determining natural resistance to human immunodeficiency virus (HIV-1) infection. In the present study, the samples of Russians (n = 107), Tuvinians (n = 50), and HIV-infected individuals were examined for the presence of CCR5del32 mutation in the CCR5 gene. The CCR5del32 allele frequency in Russians and Tuvinians constituted 7.84 and 2%, respectively. Among HIV-1 infected individuals, two groups, of macrophage-tropic HIV-1 strain- and T-cell-tropic HIV-1 strain-infected were distinguished. The CCR5del32 allele frequency in the first group (6.45%) was lower than in the second one (8.73%). Statistical treatment of the HIV-1 infected individuals typing data showed that the difference in the CCR5del32 allele frequencies between the groups of sexually (macrophage-tropic) and parenterally (T-cell-tropic) infected individuals observed was within the limit of random deviation.
Allele frequency distribution of CTG-repeat in the 3'-flanking region of DMPK gene was analyzed in populations of Yakutia (three ethnogeographical groups of Yakuts, Evenks, Evens, Yukaghirs, Dolgans) and Central Asia (Kazakhs, Uzbeks, Uighurs). Frequencies of CTG alleles were found to be significantly different in two regions. Allele frequency distribution in populations of Yakutia was similar to Asian populations, whereas Central Asian populations showed similarity to European populations. The features of allele spectrum in Yakut populations were discussed in terms of high prevalence of myotonic dystrophy in Yakuts. Our result supports the hypothesis of founder effect in spread of myotonic dystrophy in Yakuts. The phylogenetic relationships between the investigated populations based on polymorphism of CTG-locus of the DMPK gene have been analyzed as well.