Do reduced levels of steroid 21-hydroxylase confer a survival advantage in fetuses affected by sex chromosome aberrations?

Revisiting the prevalence of nonclassic congenital adrenal hyperplasia in US Ashkenazi Jews and Caucasians

Purpose

Nonclassic 21-hydroxylase deficiency, a mild form of congenital adrenal hyperplasia (CAH), is estimated to be the most common autosomal recessive condition, with an especially high prevalence in Ashkenazi Jews (3.7% affected, 30.9% carriers), based on a 1985 HLA-B linkage study of affected families. Affected individuals, especially women, may suffer from hyperandrogenism and infertility. State-of-the-art genetic studies have not been done to confirm these remarkable rates.

Methods

CYP21A2 genotyping was performed in 200 unrelated healthy Ashkenazi Jewish subjects and 200 random US Caucasians who did not self-identify as a specific ethnicity using multiplex minisequencing, real-time polymerase chain reaction and junction site analysis.

Results

Nonclassic CAH carriership was found similarly in 15% (95% confidence interval (CI): 10.4–20.7) of Ashkenazi Jews and 9.5% (95% CI: 5.8–14.4) of Caucasians (P=0.13). The proportion of Ashkenazi Jewish nonclassic CAH carriers (0.15 versus 0.309, P<0.0001) and disease affected (0.005 versus 0.037, P=0.009) was not as high as previously reported. The estimated prevalence of nonclassic CAH in Caucasians was 1 in 200 (0.5%, 95% CI: 0.01–2.8).

Conclusion

Nonclassic CAH is a common condition, regardless of ethnicity, and should be considered with preconception and infertility counseling.

Premature pubarche in a child with abnormal 3β-hydroxysteroid dehydrogenase function and Klinefelter syndrome: the intriguing relationship between androgen deficiency and excess

Disorders of androgen excess may coexist with disorders of androgen deficiency, such as Klinefelter syndrome, and can create diagnostic and therapeutic challenges.

A rare combination: congenital adrenal hyperplasia due to 21 hydroxylase deficiency and Turner syndrome

A combination of Turner syndrome (TS) and classical congenital adrenal hyperplasia (CAH) is rare. A one-day-old newborn was referred to our hospital with ambiguous genitalia. The parents were third-degree relatives. The infant's weight was 3350g (50-75p), and the head circumference was 34.5cm (50p). The gonads were nonpalpable. Presence of a 3 cm phallus, one urogenital opening into the perineum, and incomplete labial fusion were identified. Laboratory tests revealed a classical type of CAH due to 21-hydroxylase deficiency. Karyotyping revealed a 45X0(35)/46XX(22) pattern with negative sex-determining region Y (SRY) on gene analysis. At the most recent follow-up visit, the patient appeared to be in good health - her height was 70.4 cm [-1.5 standard deviation (SD)] and her weight was 9.8 kg (0.3 SD). She was receiving hydrocortisone in a dose of 10 mg/m²/day, fludrocortisone acetate in a dose of 0.075 mg/day, and oral salt of 1 g/day. System examinations were normal. The patient's electrolyte levels were found to be normal and she was in good metabolic control. The findings of this patient demonstrate that routine karyotyping during investigation of patients with sexual differentiation disorders can reveal TS. Additionally, signs of virilism should always be investigated at diagnosis or during physical examinations for follow-up of TS cases. SRY analysis should be performed primarily when signs of virilism are observed. CAH should also be considered in patients with negative SRY.

Autoimmunity and Turner's syndrome

Turner Syndrome (TS) is a common genetic disorder, affecting female individuals, resulting from the partial or complete absence of one sex chromosome, and occurring in approximately 50 per 100,000 liveborn girls. TS is associated with reduced adult height and with gonadal dysgenesis, leading to insufficient circulating levels of female sex steroids and to infertility. Morbidity and mortality are increased in TS but average intellectual performance is within the normal range. TS is closely associated to the presence of autoantibodies and autoimmune diseases (AID), especially autoimmune thyroiditis and inflammatory bowel disease. Despite the fact that the strong association between TS and AID is well known and has been widely studied, the underlying immunopathogenic mechanism remains partially unexplained. Recent studies have displayed how TS patients do not show an excess of immunogenic risk markers. This is evocative for a higher responsibility of X-chromosome abnormalities in the development of AID, and particularly of X-genes involved in immune response. For instance, the long arm of the X chromosome hosts a MHC-locus, so the loss of that region may lead to a deficiency in immune regulation. Currently no firm guidelines for diagnosis exist. In conclusion, TS is a condition associated with a number of autoimmune manifestations. Individuals with TS need life-long medical attention. As a consequence of these findings, early diagnosis and regular screening for potential associated autoimmune conditions are essential in the medical follow-up of TS patients.