Molecular genetic study on sex determination, differentiation and sexual differentiation anomaly.

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In a total of 40 individuals from 19 cases (25 samples from 10 cases of phenotypic females including 3 Turner's syndrome, and 15 samples from 9 cases of phenotypic males), which was presumed as sex differentiation anomaly by clinical and cytogenetic findings, peripheral blood, cord blood, skin, gonad, bucal cells, born marrow, amniotic fluid and placental chorionic villi were examined by FISGH,Southern blot hybridization, PCR and direct DNA sequencing for X (3 loci) and Y chromosomes (27 loci). Marker chromosomes were demonstrated that 2 cases were derived from X and 7 were derived from Y by using G,Q banding and FISH.Among the samples analyzrd, a total of 15 ceses including of these 7 cases from Y,3 cases of 45, X/46, XY,2 cases of gonadoblastoma (XX,XY), 2 cases of ambiguous external genitalia (XX,XY) and 1 cases 0f small Y,a case of ovotestis with 46, XX (peripheral blood and both right and left gonads), and XX male with hypospadias and cryptorchild testis (petipheral blood) were found any Y contents. A case of monozygotic twins of discordant sex both with 47, X,idic (Yp)*2/45, X/46, X,idic (Yp) mosaicism was demonstrated to lack from Yq11.2 to Yq terminal. A case of dizygotic twins of discordant sex was revealed to be blood chimerism. In 2 cases of 46, X,+mar, the markers were demonstrated derived from a Y chromosome including P terminal to q11.23 and paracentric inversion in the remained Y long arm, and i (Y) (p10) individually. Five cases of Phenotypic female with 46, X,+mar, mosaicism of 45, X cell line were found in several tissue including gonads. No deletion and mutation were demonstrated in SRY positive cases.The present report illustrates the importance of mosaicism in relation to sex chromosome, and FISH and molecular techniques as a complement to cytogenetic method for accurate identification and characterization of chromosome rearrangements in "sex determination"and "sex differentation".