Ring Chromosome Y

Cases with ring chromosome Y (RCY) were detected using karyotyping, fluorescence in situ hybridization (FISH), Southern blotting, PCR analysis, and chromosome microarray analysis (CMA) to define their ring structure, dynamic mosaicism, and genomic imbalance. Prenatal and postnatal diagnosis should include direct FISH testing for mosaicism, as well as standard culture, as the RCY can be lost during culture. The genetic counseling for pregnancies with RCY can be difficult since there is a wide range of phenotypes and phenotypes do not appear to correlate with chromosome mosaicism in the blood. The majority of postnatal cases are males who present with phenotypes ranging from normal male to males with short stature and infertility, to patients with ambiguous external genitalia, to a few females with gonadal dysgenesis, to females with Turner syndrome. Due to the association of the Y chromosome with germ cell tumors, those patients with gonadal dysgenesis should have follow-up with regular examinations and serum tumor markers. Screening for cardiac and renal abnormalities, as well as gonadal abnormalities are recommended.