High Prevalence of Associated Birth Defects in Congenital Hypothyroidism

Congenital hypothyroidism is one of the common and readily preventable causes of mental retardation. Prevalence of sporadic congenital hypothyroidism is 1 in 2500–4000 [1, 2]. In India the prevalence has been reported to be 1 in 2640 [2]. National neonatal screening programs are in place in developed countries to facilitate early diagnosis and treatment to prevent irreversible sequelae, that is, short stature and mental retardation [3–6]. Unfortunately there is no such ongoing program, nor is there any detailed registry of congenital hypothyroidism patients in India.There are reports of a high prevalence of associated congenital anomalies ranging from congenital heart disease to neural tube defects in this population [7–11]. However, the prevalence of these has been variable in the different ethnic groups [12–14]. A high frequency of birth defects suggests the possible role of common genes or intrauterine factors in multiple organ differentiation, including the thyroid. Indeed there is some evidence to suggest that defects in genes involved in thyroidogenesis can also cause cardiac anomalies [15, 16].No data on the prevalence of common birth defects in patients with congenital hypothyroidism is available from India. We planned this study to rigorously and systematically identify and document dysmorphic features cardiac, skeletal, and urogenital anomalies in patients of congenital hypothyroidism being followed up in our pediatric endocrinology clinic.This ongoing cross-sectional study is being conducted in patients diagnosed to have congenital hypothyroidism, being followed up in Pediatric Endocrinology Clinic, Sri Venkateswara Institute of Medical Sciences, Tirupati, a tertiary care centre.All children presenting to our clinic with biochemically confirmed primary hypothyroidism (low triiodothyronine, low thyroxine, and thyrotropin 10？IU/mL) having an early infantile or neonatal onset of symptoms, such as delayed developmental milestones, short stature, mental retard