Self-Assessment Questions

11. Puberty in boys

• In patients with Klinefelter syndrome, what presumably causes their unusually tall height?

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  Correct answer:
  Scientists have determined that genes determining linear bone growth appear to be carried on the distal short arm of the X chromosome and that this area does not seem to undergo X inactivation. Thus, this locus will have a vital role in determining final adult height. Patients with Klinefelter syndrome have a 47 XXY karyotype and therefore are believed to have a double dose of X-linked stature determinants in addition to their height advantage from being male.