Early Androgen Deficiency in Infants and Young Boys with 47,XXY Klinefelter Syndrome

Abstract

The physical phenotype in infants and young boys with KS (1-23 months old) includes normal auxologic measurements and early evidence of testicular failure. Muscle tone was decreased in most of the boys. Testicular volume and penile length were diminished, indicating early androgen deficiency. The neonatal surge in testosterone was attenuated in our KS population. Thus, infants and young boys with KS have evidence of early testicular failure. The etiology of this failure and the clinical role of early androgen replacement require further study.