An XX male with the sex-determining region Y gene inserted in the long arm of chromosome 16.
OBJECTIVE: To report a case of a 46,XX male with an insertion of the sex-determining region Y (SRY) region in the terminal end of the long arm of chromosome 16. DESIGN: Case report. SETTING: Molecular and cytogenetic units in a university hospital. PATIENT(S): An infertile male, with normal masculinization of the external genitalia, who was referred for chromosomal analysis as an unaffected member of a family with idiopathic hypertrophic osteoarthropathy. INTERVENTION(S): Cytogenetic investigation, physical examination, and hormonal assays. MAIN OUTCOME MEASURE(S): Chromosomal analysis using GTG banding and fluorescence in situ hybridization (FISH). RESULT(S): Conventional chromosome analysis revealed a normal 46,XX karyotype. The FISH with bacterial artificial chromosomes (BACs) of the SRY region indicated the presence of this region on the terminal end of the long arm of chromosome 16. CONCLUSION(S): This is the first case of a 46,XX male with the SRY gene present on an autosome-here chromosome 16. The size of the inserted region containing SRY, inserted in 16qter, is approximately 600 kb.