Friday, September 15, 2017

Congenital Adrenal Hyperplasia (CYP21A2) sequencing, biological sample

New Test in NOÛS Catalog
Test Code: 7448
Biological Sample
Sequencing Method
Set Up Days:
Delivery term:
37 days
Congenital Adrenal Hyperplasia (CAH) is a hereditary endocrine disorder caused by a steroidogenic enzyme deficiency that is characterised by adrenal insufficiency and variable degrees of hyper- and hypo- androgenic manifestations, depending on the type and the severity of the disease. Prevalence is estimated at 1/10,000 and the annual incidence varies from 1/5,000 to 1/15,000. The most common form of CAH is the classic 21-hydroxylase deficiency, which can be further divided into the simple virilising form and the salt-wasting form. Girls have ambiguous genitalia at birth and varying levels of virilisation. They have a normal uterus but an anomalous development of the vagina. The external genitals in boys are normal. The salt-wasting forms of CAH lead to symptoms of dehydration and hypotension in the first weeks of life and can be potentially mortal. Non-classic CAH (NCAH) of often not diagnosed until adolescence when the first symptoms appear. The manifestations in women are hirsutism, acne, anovulation and menstrual irregularities. Males (and some females) are asymptomatic. In 0-5% of the cases, CAH is caused by a mutation in the CYP21A2 gene, localised in the chromosome 6p21.3 which encodes for an enzyme that controls the synthesis of cortisol and aldosterone. Other genes are involved with less frequency and lead to the following CAH variants: - CAH due to 17-alpha-hydroxylase deficiency (CYP17A1 gene), - CAH due to 3-beta-hydroxysteroid dehydrogenase deficiency (HSD3B2 gene), - CAH due to 11-beta- hydroxylase deficiency (CYP11B gene), - CAH due to cytochrome P'50 oxidoreductase deficiency (POR gene), - CLAH or congenital lipoid adrenal hyperplasia (STAR gene). CAH is an autosomal recessive disorder and genetic counselling should be offered. Dexamethasone can be administered to pregnant women at risk of having descendants with the mutation (when the foetus is feminine) to prevent virilisation. OTHER TESTS IN CATALOGUE 1176, 32'2

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