Ambiguous genitalia, 45,X/46,XY mosaic karyotype, and Y chromosome microdeletions in a 17-year-old man.

OBJECTIVE

To describe clinical and laboratory features of a patient with 45,X/46,XY mosaic karyotype and Y chromosome microdeletions and to discuss the diagnostic problems in his management.

DESIGN

Case report.

SETTING

University department.

PATIENT(S): A 17-year-old man with ambiguous genitalia, 45,X/46,XY mosaic karyotype, and Y chromosome microdeletions.

INTERVENTION(S): Testicular ultrasonography, karyotype, open testicular biopsy, polymerase chain reaction (PCR) screening for cystic fibrosis, PCR screening for Y chromosome microdeletions in peripheral blood and testicular tissue, and reverse transcriptase PCR in testicular tissue for Y chromosome microdeletions.

MAIN OUTCOME MEASURE(S): Avoidance of dissemination of testicular cancer.

RESULT(S): The patient was referred for bilateral orchiectomy.

CONCLUSION(S): 45,X/46,XY mosaic karyotype is associated with a broad spectrum of phenotypes that includes female with Turner syndrome, male with mixed gonadal dysgenesis, male pseudohermaphroditism, and apparently normal male. Microdeletions of the long arm of the Y chromosome may be associated with Y chromosomal instability, leading to formation of 45,X cell lines. 45,X/46,XY males carry an increased risk for gonadal tumors and must be followed closely.