Abstract
Congenital adrenal hyperplasia (CAH) describes a group of autosomal recessive disorders of steroid biosynthesis, in 95% of cases due to 21-hydroxylase deficiency. The resulting hormonal imbalances lead to increased 17-hydroxyprogesterone and androgens levels, at the expense of decreased concentrations of glucocorticoids and, in some cases, of mineralocorticoids. A variety of clinical presentations accompany a range of severities, which are described as different forms of CAH, and are the result of these hormonal imbalances. The incidence of CAH worldwide is approximately 1 in 15,000 live births, and is population-dependent; thus, its inclusion in neonatal screening tests is widely discussed. Diagnosis of CAH is based on the quantification of 17-hydroxyprogesterone, usually by immunoassay, which has low specificity and high false-positive rates, resulting in a relatively high demand for a second-tier confirmation test. We report a case of a newborn recognized as female at birth, but showing ambiguous genitalia and other CAH clinical features, including hypernatremia, in the first days of life. In addition to the classical assays, liquid chromatography–tandem mass spectrometry was used to determine the serum steroid profile, allowing for the accurate and simultaneous quantification of seven steroids in the same analysis. Such an application immediately revealed an alteration in the levels of specific steroids related to CAH, leading to an early intervention by hormone replacement therapy. Subsequently, the diagnosis of classic CAH due to 21-hydroxylase deficiency was further confirmed by molecular testing.
Highlights
Congenital adrenal hyperplasia (CAH), the most common adrenal gland disorder in newborns and children, is a group of autosomal recessive disorders characterized by inherited defects in steroid biosynthesis [1]
As highlighted in the present case, a newborn with ambiguous genitalia is a clinical emergency, and requires appropriate investigations to be conducted quickly, as a correct diagnosis followed by early treatment is crucial in this inborn error of steroid biosynthesis [13]
It is worth noting that CAH is the most common cause of ambiguous genitalia in newborns, and that 21-OHD represents the cause of about 95% of CAH cases [2,14]
Summary
Congenital adrenal hyperplasia (CAH), the most common adrenal gland disorder in newborns and children, is a group of autosomal recessive disorders characterized by inherited defects in steroid biosynthesis [1]. The cause of about 95% of CAH cases is a 21-hydroxylase deficiency (21-OHD), which is the result of CYP21 gene mutations. CAH may include a variety of clinical symptoms, such as poor feeding, failure to thrive, vomiting, dehydration, hyperkalemia, hyponatremia, metabolic acidosis, apathy, virilization, androgen excess, possible salt-wasting crisis as a result of aldosterone deficiency, and incorrect gender assignment [4]. Androgen excess in females with CAH can cause virilization of the external genitalia, resulting in an altered body, behavior, and sexuality, while androgen excess in male patients is not as profound as in females. The variety of clinical presentations leads to a range of severities describing different forms of CAH. An LC–MS/MS method for the determination of steroid profiling for the rapid confirmation and early treatment of CAH is extremely useful in clinical practice. The application of a steroid profile by LC–MS/MS immediately highlighted the alteration in the levels of some steroids related to 21-OHD, allowing for an early intervention by hormone replacement therapy in the first days of life
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