A Girl with 45,X/46,XX Turner Syndrome and Salt Wasting Form of Congenital Adrenal Hyperplasia Due to Regulatory Changes

The incidence of Congenital Adrenal Hyperplasia (CAH) is 1:10,000 - 16,000 worldwide, of which 90% occurs in the CYP21A2 gene coding for steroid 21-hydroxylase. On the other hand, Turner's syndrome, with an incidence of 1:2500, is a form of gonadal dysgenesis which leads to early ovarian failure and other phenotypic changes such as webbed neck, widely-spaced nipples and short stature. Here, we present a girl suffering from both 45,X/46,XX Turner's syndrome and salt wasting (SW) form of CAH. Clinical and biochemical examinations were performed for the patient. Cytogentic studies and molecular testing such as allele specific PCR for eight mutations in the CYP21A2 gene, multiplex ligation probe amplification (MLPA) and direct sequencing confirmed the clinical diagnosis. Heterozygous mutations in the regulatory region at positions -316 to -264 verified SW form of 21-hydroxylase deficiency. 45,X/46,XX mosaicism proved Turner's syndrome. The SW presentation of the patient may be due to the CYP21A1P microconversion. The study of regulatory changes of the CYP21A2 and gender differentiation pathways would be possible using such patients. (Clin. Lab. 2012;58:1063-1066. DOI: 10.7754/Clin.Lab.2011.110501)