Dyshormonogenesis Emerging as a Predominant Cause of Congenital Hypothyroidism in India - A Mini Review

Congenital hypothyroidism (CH) is one of the most common preventable and treatable cause of intellectual impairment in children. Among known etiologies dysgenesis due to abnormal anatomical development and dyshormonogenesis as a result of deranged physiological functioning of fetal thyroid gland. account for at least 90 % of causes of CH. While review of literature report thyroid dysgenesis as the most common etiology of CH currently focus is on iodine status adequacy in women before and during pregnancy and after delivery and lactation. Worldwide reports of previously iodine sufficient countries declared presently as iodine insufficient and recent publications of several Indian states consuming lesser amounts of iodized salt seem to indicate that iodine related pathophysiological factors are emerging as predominant etiologies of CH. The most vulnerable pregnant women and newborns are prone to be affected with iodine imbalances leading to pregnancy and perinatal related complications. Analysis of demographic, biochemical, clinical and statistical data by Indian Council of Medical Research (ICMR) in a multi-centric pilot study on congenital hypothyroidism has clearly shown that dyshormonogenesis is a leading cause of CH in neonates born in India. The need of the hour is to consider mandatory newborn screening for CH in all live newborns and further conduct country wise ethnic and culture oriented research studies with special emphasis on iodine status, genetic predispositions and lifestyle changes impact on all vulnerable populations and design effective early therapeutic strategies for management of CH to prevent intellectual impairment.