Presence of Y chromosome sequences and their effect on the phenotype of six patients with Y chromosome anomalies.

The extent of Y chromosome material was determined in 6 southern African subjects with sex chromosome anomalies. Four of the subjects were phenotypically female, and 2 were phenotypically male. Molecular and cytogenetic findings were correlated with phenotypic expression. An X;Y translocation was found in both male subjects, and in one female subject. The remaining female subjects were characterized by an isodicentric Y, an isochromosome Yq, and a micromarker of undetermined origin, respectively. The individuals were tested for the presence of a number of Y-specific DNA sequences. Molecular findings were generally compatible with the cytogenetic findings, and also with the phenotypic sex of the patients. All the female subjects had Y material and all but one were negative for the sex determining region of the Y (SRY). The somatic Ullrich-Turner-like findings present in 3 of the females were attributed to either the presence of a 45,X cell line and/or a single copy of Xp. The males both showed X;Y translocations without any detectable loss of Y DNA. Although molecularly very similar, the disparate clinical findings in these 2 subjects could have been accounted for by different X inactivation patterns.