This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pediatrics
Most common cause of Neonatal Hypothyroidism is 
Select and explain. 
A. Throid dysgenesis, B. Transplacental maternal thyroid antibodies, C. Inherited genetic disorders, D. Decreased thyroglubin
A: Throid dysgenesis
Answer: A: Throid dysgenesis 
Explanation: Iodine deficiency is the commonest cause of congenital hypothyroidism in ceain pas of India, while thyroid dysgenesis is the most common aetiology in non-endemic areas (75% of all cases). Thyroid scan pictures showing different types of thyroid dysgenesis. At upper panel hypoplasia (A), hemiagenesis (B), ectopia (C), double ectopia (D), and athyreosis (E) compared with normal thyroid (G) shown at lower panel. Panel F showing scintigraphy performed at the time of diagnosis (F1 and F2) repoed as hemiagenesis while repeated scintigraphy at the time of the study (at 12 years age) showed ectopia (F3). Radiopharmaceutical uptake by thyroid tissue is shown by black arrows and salivary glands by empty arrows. Reference: Ghai essential of paediatrics, eighth edition, p.no:516