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

ABSTRACT

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.