Novel StAR Gene Mutation Identified in a Moroccan Patient with Lipoid Congenital Adrenal Hyperplasia
Congenital Adrenal Hyperplasia (CAH) is an autosomal recessive condition that results from the deficiency of one of the steroidogenesis enzymes responsible for cortisol biosynthesis. In the majority of cases, CAH is caused by 21-hydroxylase deficiency. More rarely, the deficiency concerns 11b-hydroxylase, 3b-hydroxysteroid dehydrogenase, 17hydroxylase, or exceptionally StAR and P450 oxydoreductase. Here, we report the case of a 3 year and 4 months old male child, born from a consanguineous marriage who presented at 15 months old with the salt-loss syndrome. Physical examination found generalized melanoderma, micropenis and bilateral cryptorchidism. Biological assessment at the time of diagnosis revealed hyponatremia, hyperkalemia, functional renal failure, hypoglycemia, low blood cortisol level, and high blood level of ACTH, suggesting primary adrenal insufficiency. The patient presented also with the abnormality of sexual differentiation with a 46 XY karyotype, testosteronemia level was low at the baseline and after HCG stimulation, pelvic ultrasound and Magnetic Raisonance Imaging (MRI) showed bilateral testicular atrophy in the inguinal position. The genetic study revealed a likely pathogenic homozygous variant in the StAR (steroidogenic acute regulatory) gene. Therapeutically, our patient was hydrated by saline solution and treated with hydrocortisone and fludrocortisone, then benefited from a surgical testicular correction marked by a favorable evolution. Although mutations in StAR gene are rare, they can be responsible for the defect in the early stage of steroidogenesis and therefore cause a deficiency in adrenal and sexual hormones biosynthesis.
Keywords:StAR gene, Mutation, Congenital adrenal hyperplasia, Disorders of sex development
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