Atypical Congenital Adrenal Hyperplasia (CAH) Presentation of A Patient, Resulting in A Similar Diagnosis for His Sibling

Introduction: Congenital adrenal hyperplasia (CAH) is the commonest cause of primary adrenal insufficiency and is known to be transmitted in an autosomal recessive manner. We report two cases of male siblings with CAH. Cases: The elder sibling was diagnosed late at 4 years old with signs of virilization, complicated with central precocious puberty (CPP). The younger sibling was diagnosed after baseline screening and stimulation test. Treatment with both hydrocortisone and fludrocortisone were commenced for both siblings once the diagnosis was made. The elder sibling however, required treatment with gonadotropin analogues to treat the CPP.  Conclusion: These cases illustrate the importance of an early diagnosis of CAH and the benefit of screening siblings to prevent late presentations of CAH in high-risk families.