Precocious puberty in male with hypertension and hypokalemia; a definite diagnostic clue for 11β hydroxylase deficiency CAH.

Summary: 11β-hydroxylase deficiency (11βOHD) (5-7%) is an uncommon cause of congenital adrenal hyperplasia compared to 21-hydroxylase deficiency (21OHD) (90%). We report a case of a 5-year-old boy who presented with gonadotropin-independent precocious puberty along with hypertension, generalized hyperpigmentation and hypokalemia. 17-hydroxyprogesterone came raised along with low stimulated cortisol. With the unavailability of urinary steroid profiling and serum 11-β deoxycortisol levels, we went ahead with molecular analysis of the patient. It confirmed exon deletion (1-6) of CYP11B1 and exon deletion (8-9) of the CYP11B2 gene, and the diagnosis of 11βOHD was substantiated. The patient was started on oral hydrocortisone tablet and responded promptly regarding blood pressure normalization and hypokalemia resolution. This case highlights the importance of discriminatory features of hypertension and hypokalemia, which can effectively differentiate from 21OHD to 11βOHD clinically. In addition, we have reported a comparatively rare genetic finding of 1-6 exon deletion in the CYP11B1 gene. Learning points: CYP11B1 OHD should be considered one of the primary differentials for boys presenting with precocious puberty and hypertension. 11βOHD can cause childhood-onset salt-wasting episodes and, later, significant hypertension with precocious puberty. Increased 17-hydroxyprogesterone can be found in both 21OHD and 11 βOHD cases; significant hypertension and hypokalemia are discriminatory clinical findings besides renin, aldosterone assay and molecular analysis. Prompt initiation of glucocorticoids, the mainstay of the treatment of 11βOHD, retards pubertal progression and normalizes blood pressure. Additional antihypertensives can be used in refractory cases.