pediatrics
Klinefelter Syndrome (47,XXY)
Diagnosis of Klinefelter Syndrome
Prenatal diagnosis often when cytogenetic testing is done for other reasons such as advanced maternal age Detected postnatally on clinical appearance Cytogenetic testing by karyotyping, fluorescent in situ hybridization (FISH) analysis, and/or chromosomal microarray analysis The diagnosis of Klinefelter syndrome is suspected based on physical examination of an adolescent with small testes and gynecomastia. Many men are diagnosed during an infertility evaluation (probably the majority of nonmosaic 47,XXY males are subfertile). Diagnosis is confirmed by cytogenetic analysis (karyotyping, FISH analysis, and/or chromosomal microarray analysis). (See also Diagnosis and 