Etiological Evaluation of Congenital Hypothyroidism in Cases Referred From The National Screening Program

INTRODUCTION: Congenital hypothyroidism is defined as the deficiency of thyroid hormones in newborn babies, with the incidence of 1 in 1400 to 2800. The aim of this study is to evaluate cases referred from the congenital hypothyroidism (CH) newborn screening program.
METHODS: 135 cases with high capillary TSH who were referred from the national screening program between January 2017–July 2019 were included in the study.
RESULTS: 48 of 135 cases (35.6%) were diagnosed as CH. The mean onset of treatment was 17.31 ± 9.92 days. Clinical findings suggesting hypothyroidism were detected in 27 patients (56.2%) and goiter was detected in 2 patients (4.1%). According to imaging findings 16 (35.5%) patients were diagnosed as dysgenesis [1 (2.2%) agenesia, 3 (6.7%) ectopia, 12 (26.6%) hypoplasia), 11 were as dyshormonogenesis (24.5%), 18 were as eutopic thyroid (40%). Mean levothyroxine dose was 12.7±2.5 mcg/kg/day and the mean onset of treatment in 30.4% of diagnosed patients were in first 14 days and 93.3% were in first 30 days.
DISCUSSION AND CONCLUSION: Dysgenesis and dyshormonogenesis are the most common detectable causes of congenital hypothyroidism. The normal localization of the thyroid gland in about half of the patients suggests that transient causes of CH may be more common than expected. Considering that only 1/3 of the patients were treated in the first 2 weeks, it was thought that referral of patients is still an important problem and should be faster.