RESUMO
PURPOSE: We investigated the clinical characteristics and relationship between chromosome and its phenotypic expression in patients with 45 XO/46XY mosaicism or 45 XO with SRY gene. MATERIALS AND METHODS: 11 patients with 45XO/46XY chromosomal abnormality and 4 patients with 45XO with SRY positive reaction admitted from 1990 to 1996 were evaluated. Patients were grouped according to chromosome and gonadal expression. Group A consisted of patients with 45XO/46XY chromosome and unilateral streak gonad, group B patients with 45XO chromosome, SRY positive reaction and unilateral streak gonad and group C patients with 45XO/46XY chromosome and bilateral streak gonads. RESULTS: Of the total 15 patients, the number of patients in group A, B, and C were 8, 4, and 3, respectively. SRY gene was positive in all group A and B patients but only one patient was positive in group C. Of the 8 patients in group A, 5 patients had a high XY mosaicism ratio compared to XO whereas an equal ratio was observed in the remaining 3 patients. Of the 4 male penotype patients only 1 patient had a high XY mosaicism ratio compared to XO while 3 patients displayed an equal ratio. There was no difference in associated anomaly and the degree of severity of ambiguity according to the mosaicism ratio in all patients. CONCLUSIONS: There was no definite correlation between the mosaicism ratio and phenotypic expression. Presence of SRY gene in 45XO patients may suggest MGD(mixed gonadal dysgenesis) and therefore, the evaluation SRY gene could be useful in the diagnosis of 45XO patients with ambiguous genitalia.