Early androgen deficiency in infants and young boys with 47,XXY Klinefelter syndrome.
ABSTRACT Klinefelter syndrome (KS) is characterized by the karyotype 47,XXY. In this study, we evaluated the physical and testicular failure phenotypes of infants and young boys with KS.
The evaluation included auxologic measurements, biologic indices of testicular function, and clinical assessment of muscle tone in 22 infants and young boys with KS, ages 1-23 months.
Mean length, weight, and head circumference in SDS were generally within the normal range at -0.3 +/- 1.0, -0.1 +/- 1.4, and 0.0 +/- 1.5, respectively. Mean penile length and testicular volume SDS were -0.9 +/- 0.8 and -1.1 +/- 0.8, indicating significantly reduced penile and testicular size. Mean testosterone levels for the boys < or =6 and >6-23 months were 128 +/- 131 (4.4 +/- 4.5 nmol/l) and 9.5 +/- 7.2 ng/dl (0.3 +/- 0.2 nmol/l), respectively. High-arched palate was observed in 6/17 boys and clinodactyly (5th finger) was observed in 15/16 boys. Hypotonia was evaluated clinically and was noted to be present in 12/17 boys.
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.
- Birth defects original article series 02/1982; 18(4):99-154.
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ABSTRACT: Klinefelter syndrome is a major cause of infertility in the male. Nevertheless, pregnancies were recently obtained by intracytoplasmic injection of sperm retrieved by surgery or ejaculation, underscoring the need to understand the role of Sertoli and Leydig cell secretions during development. In 18 infants with prenatally diagnosed homogenous 47,XXY karyotype, blood samples were taken from birth to 3 yr of age. Inhibin B (INHB), anti-Müllerian hormone (AMH), testosterone, FSH, and LH levels were compared with those in six adolescents with XXY karyotype and reference values established in 215 control infants. In XXY infants FSH, LH, INHB, and AMH did not differ from controls. Testosterone levels during the first trimester exhibited a physiological increase but were lower than in controls (P = 0.0001). Significant correlations were found between testosterone and LH (P < 0001), between INHB and FSH (P = 0.0011), and between AMH and INHB (P = 0.025). In XXY adolescents, AMH and INHB were undetectable. Our findings demonstrate that testosterone secretion is impaired in infants with Klinefelter syndrome. By contrast, INHB and AMH secretions were not altered, which raises the question of the mechanism(s) governing the decline of Sertoli cell function after puberty.Journal of Clinical Endocrinology & Metabolism 04/2004; 89(4):1864-8. · 6.43 Impact Factor
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ABSTRACT: The aim of the study was to investigate the longitudinal changes of inhibin B in a group of patients with Klinefelter syndrome (KS; karyotype 47,XXY) progressing through puberty and to compare them to a group of age- and puberty-matched controls. Seven boys with nonmosaic KS (karyotype 47,XXY) and 11 controls were followed with longitudinal serum inhibin B measurements every 3-12 months as they approached and entered puberty. None of the boys had significant bone age delay, and all entered puberty at the normal time and progressed through it at the expected time. In addition, 15 young adults with KS, aged 16.7-29.5 yr, were studied. We found normal levels of inhibin B in prepubertal boys with KS and controls. In patients with KS as well as controls, inhibin B increased progressively before clinical pubertal onset. However, during late puberty inhibin B levels decreased gradually to the low/unmeasurable levels observed later in adult KS, while remaining unchanged in the controls.Journal of Clinical Endocrinology & Metabolism 03/2003; 88(2):888-91. · 6.43 Impact Factor