• Obvious from studying sex chomosome abnormalities such as Klinefelter syndrome (causes XXY males) and Turner syndrome (causes X females). (
  • Klinefelter syndrome (KS) is an inheritable disorder of males characterized by hypogonadism, mild mental retardation, and a karyotype of 47, XXY. (
  • Klinefelter syndrome is found in about 1 out of every 500-1,000 newborn males. (
  • Males who have Klinefelter syndrome may have the following symptoms: small, firm testes, a small penis, sparse pubic, armpit and facial hair, enlarged breasts (called gynecomastia), tall stature, and abnormal body proportions (long legs, short trunk). (


  • This chapter concentrates on Klinefelter syndrome and Turner syndrome. (
  • Turner syndrome (TS) is an inheritable disorder of females characterized by short statue, premature ovarian failure, and a karyotype of 45,X with or without mosaicism. (


  • Except prenatal diagnosis for other reasons, such as old maternal age, Down syndrome, as well as others, KS usually is not diagnosed after birth and during infancy. (