Do we Need Newborn Screening for Congenital Adrenal Hyperplasia?
Dept Child Health Faculty of Medicine Universitas Indonesia Endocrinology Working Group Indonesian Pediatric Society
Congenital Adrenal Hyperplasia (CAH) is an autosomal recessive genetic disorder due to enzyme deficiencies in the adrenal steroidogenesis pathway. Incidence is 1 in 15000 to 20000 livebirth globally. The most common is 21-hydroxylase deficiency (21-OHD) occurring in 90 to 95% with a death rate of 9%. In 21-OHD, 17 hydroxyprogesterone (17-OHP) accumulates and is diverted to androgen synthesis. Mineralocorticoid deficiency may occur in 21-OHD resulting in salt wasting episodes. Salt Wasting (SW) is most prevalent in 21-OHD (75%), and is potentially life threatening. Adrenal crisis usually occurs in the 2nd week of life. Female fetuses affected by classical CAH develop ambiguous genitalia (clitoromegaly) and may need surgical intervention, depending on the severity of virilization. Ambiguous genitalia itself is a social emergency situation for the parents and the child.
Hyponatremia and hyperkalemia due to adrenal insufficiency puts further insult for the growing infant. Newborn screening (NBS) for CAH (NBS-CAH) is currently conducted in a number of countries. The redundancy to launch NBS-CAH includes the cost-effectiveness, the assay, laboratory reference values, and the objectives of screening itself. If the aim is to detect all subjects with CAH, then screening will be inefficient with a high rate of false-positive and false-negative results. NBS-CAH is beneficial for preventing adrenal crisis, especially affected boys, to help make the appropriate sex assignments in affected female patients and to normalise the electrolyte imbalance.
NBS-CAH in Indonesia is not yet available. Important data to consider launching NBS- CAH in Indonesia are: basic immunisation coverage (2016) was 91.2%; IMR is 23 per 1000 live born, national health expenditure is less than 3% of GDP, government commitment, financial cover, high premature birth rate, treatment costs, drug availability, uneven distribution of pediatric endocrinologists, technician and reliable laboratory throughout the country.
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