This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Gland, Subject name: Pediatrics
Most common cause of congenital hypothyroidism: (Repeat) 
Select and explain. 
A. Thyroid dysgenesis, B. Maternal antibodies, C. Inborn errors of thyroid hormone defects, D. Maternal iodine deficiency
A: Thyroid dysgenesis
Answer: A: Thyroid dysgenesis 
Explanation: Ans: A (Thyroid dysgenesis) Ref: Nelsons Textbook of Pediatrics. 19th Edition. Pg.1895Explanation:"Most cases of congenital hypothyroidism results from thyroid dysgenesis "(Ref: Nelson)Refer 2013 Pediatrics Question Explanation