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The results of clinical, genealogical, cytogenetic and molecular genetic studies of 113 patients from 96 families with different forms of mental retardation from Ukraine are presented. This study was held as part of the CHERISH project of the 7-th Framework Program. The aim of the project is to improve diagnostics of mental retardation in children in Eastern Europe and Central Asia through detailed analysis of known chromosomal and gene's aberrations and to find the new gene-candidates that cause mental retardation. All patients have normal chromosome number (46XY or 46XX). The cases with fragile-X syndrome were eliminated using molecular genetic methods. Genome rearrangements were found among 28 patients using cytogenetic analysis, multiplex ligation-dependent probe amplification (MLPA analysis) ofsubtelomeric regions and array-based comparative genomic hybridisation (array CGH screening). In 10 cases known pathogenic CNV's were identified, 11 cases are unknown aberrations; their pathogenicity is being determined. The rest cases are known nonpathogenic gene rearrangements. Obtained results show the strong genetic heterogeneity of hereditary forms of mental retardation. The further studies will allow to identificate genes candidates and certain mutations in these genes that may be associated with this pathology.

Mutations Arg124Cys, Thr538Arg, Arg555Thr, Arg555Gln, Leu558Pro, and His626Arg in TGFBI gene were analyzed by polymerase chain reaction and restriction in 84 patients with various forms of corneal stromal dystrophies from 49 unrelated families and 29 clinically healthy relatives of these patients. A new mutation in TGFBI gene, Leu558Pro, was identified in the patients with atypical lattice dystrophy. The haplotypes of four microsatellite markers surrounding TGFBI gene region were analyzed in 22 families. The data on association of genotype and phenotype suggest that the analysis of TGFBI gene mutations is important for differential diagnostics of corneal dystrophies.

The results of molecular-genetic analysis of 12 mini- and microsatellite loci in populations of different regions of Ukraine (Kiev, Kremenchug, L'vov, Lugansk, and in Crimea tatars) were presented. Allele frequencies for each locus were determined and genetic distances between analyzed populations were calculated. The results of the analysis were applied for investigation of genetic heterogeneity and biological history of populations from different regions of Ukraine.

The results of the analysis of 32 b.p. deletion in the CCR5 macrophage chemokine receptor gene in regional populations of Ukraine are presented. The frequency of this mutation ranged from 9.1% to 11% in the Slavs populations but in the population of Crimea Tartars the frequency of mutation was only 5%.