title: Cytogenetic and molecular analysis of sex-chromosome monosomy.
abstract: X chromosome- and Y chromosome-specific DNA probes were used to study different aspects of the genesis of sex-chromosome monosomy. Using X-linked RFLPs, we studied the parental origin of the single X chromosome in 35 spontaneously aborted and five live-born 45,X conceptions. We determined the origin in 35 cases; 28 had a maternal X (Xm) and seven had a paternal X (Xp). There was a correlation between parental origin and parental age, with the Xp category having a significantly reduced mean maternal age by comparison with the Xm group. Studies aimed at detecting mosaicism demonstrated the presence of a Y chromosome or a second X chromosome in three of 33 spontaneous abortions, a level of mosaicism much lower than that reported for live-born Turner syndrome individuals.
mesh_terms: D002871:Chromosome Banding; D002872:Chromosome Deletion; D004247:DNA / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D009006:Monosomy; D012150:Polymorphism, Restriction Fragment Length; D012729:Sex Chromosome Aberrations; D014960:X Chromosome; D014998:Y Chromosome
chemical_list: D004247:DNA