Screening of patients with Turner Syndrome for "hidden" Y-mosaicism

The presence of Y-chromosomal sequences in the cells of patients with Turne r-Syndrome (TS) is a risk factor for the development of gonadal tumors. The refore and since demonstration of Y-material usually results in prophylacti c gonadectomy optimal sensitivity and specifity of the diagnosis have to be attempted. We wanted to evaluate the diagnostic potential of cytogenetic investigation s as routinely employed in TS, In the most comprehensive study published so far we screened 208 TS patients for the presence of Y-chromosomal sequence s by polymerase chain reaction (PCR) specific for eight different loci alon g the Y-chromosome. Six patients (3%) without cytogenetic evidence of Y-chromosome were found t o be Y-positive. Among 12 cases with marker chromosomes two more Y-chromoso mal fragments were identified. Thus, PCR-screening for Y-specific sequences was shown to be a valuable too l in the clinical management of Turner patients.