Summarized data of medical genetic survey of the population of Republic of Sakha (Yakutia) are presented. The number of the population examined constituted 1000700 individuals (including 424500000 of urban and 576,200 of rural population, respectively). Regarding the ethnicity, 33 regions of the Republic examined were at most inhabited by Yakuts (36%) and Russians (55%). A total of 400 families (606 patients) with autosomal dominant, 274 families (369 patients) with autosomal recessive, and 42 families (53 patients) with X-linked pathologies were detected. The segregation analysis performed showed good correlation with the expected type of inheritance for both dominant and recessive diseases. The prevalence rate of monogenic hereditary diseases for rural and urban populations, as well as for solely Yakuts, was calculated. It was shown that weighted average prevalence of dominant (0.68; 1.44) and recessive (0.43; 0.86) disorders in Yakuts was two times higher than in total population examined.
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 results of neurological, pathomorphological and clinic-genealogical studies of vilyuisk encephalitis (VE), a chronic progressive disease of CNS, are presented. The disease is spread in Yakutija in Vilyui river basin (mainly in Vilyuisk and Kobyaisk regions) exclusively among native population and is known there since the middle of the last century. The results obtained suggest that VE (despite the existing opinion on its natural-focal virus etiology) is an ethnic hereditary disease with autosomal recessive type of transmission, is spread in a limited Yakut population by an ancestor effect and gradually gets out of the limits of this population at the expense of migration. According to its clinical symptoms and pathomorphological substrate of this main neurological syndrome (peculiar lower spastic paraparesis as a result of systemic ascending degeneration of lateral corticospinal tract of spinal cord), VE belongs to hereditary heterogenous group of diseases which are referred to Strümpell's spastic paraplegia. VE is different from the diseases of this group by the occurrence of cases with very rapid progressing and characteristic brain damages. To prevent further VE accumulation, it is necessary to concentrate efforts on biochemical and neurological studies in search of reliable tests for early detection of heterozygotes. Taking into account the hereditary nature of VE, its ethnic limitations and nosological self-dependence, it is expedient to designate the disease by its local name "bokhoroor".