MOLECULAR DIAGNOSIS OF FRAGILE X-SYNDROME (SYN MARTIN-BELL) IN THE PATIENTS OF NATIVE POPULATIONS

63 families at-rist of Fragile X-syndrome (FraX) are subjected to Sout hern blot analysis with the DNA probes Ox1.9 and Ox0.55. Molecular stu dies have confirmed an initial clinical diagnosis of FraX in 26 famili es earlier studied cytogenetically and in 11 of 27 families with only some clinical traits of FraX syndrome in proband. Full mutation and pr emutation condition of FMR-1 gene was ascertained in 34 and rejected i n 18 close relatives of probands with the proved FraX syndrome in 37 a nd families. Four different patterns of pathological alleles are detec ted at electrophoregramms of DNA samples restricted by endonuclease Rc oRI and hybridized to the DNA probe Ox1.9. Prenatal diagnosis of FraX was carried out in two cases at the 1st and 2nd trimester of pregnancy . Perspective of broad application of molecular methods for early diag nostics and profilactic of FraX syndrome are briefly discussed.