How does Klinefelter syndrome affect growth patterns?

Updated: Mar 23, 2020
  • Author: Germaine L Defendi, MD, MS, FAAP; Chief Editor: Luis O Rohena, MD, MS, FAAP, FACMG  more...
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Infants and children achieve normal height, weight, and head circumference. Height velocity shows a notable increase between ages 5 and 8 years. Adults with Klinefelter syndrome are usually taller than nonaffected adult males, reaching a mean final height of about 185 cm (73 in). XXY males (see the image below) also have disproportionately long arms and legs. About 25% of patients have fifth-finger clinodactyly. Some males with Klinefelter syndrome variant 49,XXXXY have short stature.

G-banded 47,XXY karyotype. G-banded 47,XXY karyotype.

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