Congenital adrenal hyperplasia is an autosomal recessive disorder of adrenal corticosteroid biosynthesis due to deficiency of a particular enzyme. The potential clinical effects occur due to either distal hormone deficiency or accumulation of proximal metabolite with abnormal production of a steroid whose biosynthesis is unaffected. The incidence is variable and unknown in India with worldwide incidence of 1 in 13,000 children. The commonest type of congenital adrenal hyperplasia is 21 – hydroxylase deficiency. It is due to mutations in 2 genes (CYP 21 B, CYP 21 A) on short arm of chromosome 6. Patients present classically with salt wasting and with vomiting, diarrhea, dehydration, failure to thrive and adrenal crisis may manifest within first 3-4 weeks of life. There may be history of ambiguous genitalia in older sibling or sibling death due to salt wasting. Patients have pigmentation around the genitalia & all over body. There is no evidence of hypertension. Patients have hyponatremia, hyperkalemia and increased urinary sodium losses. In females virilization occurs. Males have normal looking genitalia.

The non-salt wasting types present in males with sexual & somatic precocity within 1 st 6 months of life becoming more evident by 4-5 years of age. There may be enlargement of penis, scrotum and prostrate with appearance of pubic hair and advanced bone age. Females present with some degree of masculinization at birth and breast development and menstruation does not occur in untreated cases.

The non-classic form of 21 hydroxylase deficiency presents with normal genitalia at birth in both males and females with precocious pubarche.

Diagnosis is by estimation of serum 17 hydroxy progesterone which is elevated (usually > 20 ng/ml) and increased testosterone in females. Short ACTH stimulation test may be done whereby 0.25 mg of ACTH is injected and it would lead to 2-3 fold increase in 17 hydroxy progesterone after 60 minutes but no increase in serum cortisol. Molecular genetics may be useful to detect the genetic defect.

Treatment consists of life long synthetic glucocorticoid supplementation to replace deficient cortisol and suppress over production of ACTH – Hydrocortisone is recommended in the dose of 10-20 mg/m 2/day in 2-3 divided doses. Salt wasters also require mineralocorticoid therapy. 9 Flurohydrocortisone is supplemented in the dose of 0.05-0.3 mg daily as single or 2 divided doses. Patients on breast feeding require extra sodium supplementation till weaning is established.

Patients with 21-hydroxylase deficiency require monitoring in form of anthropometry, blood pressure, bone age, status of secondary sexual characters, S.electrolytes and S. 17 OH progesterone levels once in 3-6 months. Parents need to be counseled regarding the disease and also to establish the sex of searing as early as possible. Irrespective of degree of virilization of external genitalia, genetic female should be assigned the female sex in view of normal internal genitalia and normal onset of puberty & fertility. Surgical correction of genital abnormality is required with resection of enlarged clitoris at 6-12 months and vaginoplasty with correction of urogenital sinus at a later date. There are newer modalities of treatment under trial such as use of combination of an antiandrogen, an aromatase inhibitor and lower hydrocortisone dose. Also adrenalectomy with glucocorticoid and mineralocorticoid replacement is under trial.