The objective of this study was to describe the prevalence of Klinefelter syndrome (KS) prenatally and postnatally in Denmark and determine the influence of maternal age. All chromosomal examinations in Denmark are registered in the Danish Cytogenetic Central Registry. Individuals with KS diagnosed prenatally or postnatally were extracted from the registry with information about age at the time of diagnosis and mother's age. In the period 1970-2000, 76,526 prenatal examinations on male fetuses resulted in the diagnosis of 163 fetuses with KS karyotype, corresponding to a prevalence of 213 per 100,000 male fetuses. Standardization according to maternal age resulted in a prevalence of 153 per 100,000 males. Postnatally, 696 males of 2,480,858 live born were diagnosed with KS, corresponding to a prevalence among adult men of approximately 40 per 100,000. Less than 10% of the expected number was diagnosed before puberty. Advanced maternal age had a significant impact on the prevalence. KS is severely underdiagnosed in Denmark. Only approximately one fourth of adult males with KS are diagnosed. There is a marked delay in diagnosis of the syndrome. A delay in treatment with testosterone may lead to decreased muscle and bone mass with subsequent risk of osteoporosis.

No abstract

Patients with TS and especially the karyotypes 45,X and isoXq have a higher mortality compared with the background population. TS was diagnosed with a considerable diagnostic delay. Prevalence is increasing, but incidence of TS was stable.

More emphasis should be placed on increasing the rate of diagnosis and generating evidence for timing and dose of testosterone replacement. Treatment of KS should be a multidisciplinary task including pediatricians, speech therapists, general practitioners, psychologists, infertility specialists, urologists, and endocrinologists.

AMH seems to be a promising marker of ovarian function in healthy girls and TS patients.

OBJECTIVE—Klinefelter’s syndrome is associated with an increased prevalence of diabetes, but the pathogenesis is unknown. Accordingly, the aim of this study was to investigate measures of insulin sensitivity, the metabolic syndrome, and sex hormones in patients with Klinefelter’s syndrome and an age-matched control group. RESEARCH DESIGN AN METHODS—In a cross-sectional study, we examined 71 patients with Klinefelter’s syndrome, of whom 35 received testosterone treatment, and 71 control subjects. Body composition was evaluated using dual-energy X-ray absorptiometry scans. Fasting blood samples were analyzed for sex hormones, plasma glucose, insulin, C-reactive protein (CRP), and adipocytokines. We analyzed differences between patients with untreated Klinefelter’s syndrome and control subjects and subsequently analyzed differences between testosterone-treated and untreated Klinefelter’s syndrome patients. RESULTS—Of the patients with Klinefelter’s syndrome, 44% had metabolic syndrome (according to National Cholesterol Education Program/Adult Treatment Panel III criteria) compared with 10% of control subjects. Insulin sensitivity (assessed by homeostasis model assessment 2 modeling), androgen, and HDL cholesterol levels were significantly decreased, whereas total fat mass and LDL cholesterol, triglyceride, CRP, leptin, and fructosamine levels were significantly increased in untreated Klinefelter’s syndrome patients. In treated Klinefelter’s syndrome patients, LDL cholesterol and adiponectin were significantly decreased, whereas no difference in body composition was found in comparison with untreated Klinefelter’s syndrome patients. Multivariate analyses showed that truncal fat was the major determinant of metabolic syndrome and insulin sensitivity. CONCLUSIONS—The prevalence of metabolic syndrome was greatly increased, whereas insulin sensitivity was decreased in Klinefelter’s syndrome. Both correlated with truncal obesity. Hypogonadism in Klinefelter’s syndrome may cause an unfavorable change in body composition, primarily through increased truncal fat and decreased muscle mass. Testosterone treatment in Klinefelter’s syndrome only partly corrected the unfavorable changes observed in untreated Klinefelter’s syndrome, perhaps due to insufficient testosterone doses.

Males suffering from KS experienced an increased hospitalization rate from a variety of disorders. Some are likely to be caused by hypogonadism, and some may be linked to the syndrome per se, whereas others are not readily explained. However, other factors, e.g. socioeconomic, may be involved.

Turner's syndrome is associated with glucose intolerance, diminished first-phase insulin response, elevated blood pressure, reduced FFM, and physical fitness. Sex hormone administration causes a deterioration in glucose tolerance, increases FFM and physical fitness, and has beneficial effects on blood pressure. The deleterious effect on glucose tolerance may be mediated by norethisterone, a gestagen known to have androgenic effects.