A stunted child with a protruding abdomen, short stature, and mental retardation suffers from a deficiency in what______________?
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Answer: A. Thyroxine
Explanation
Thyroxine deficiency during infancy results in congenital hypothyroidism known clinically as cretinism. Lack of thyroid hormone stunts skeletal growth and severely impairs neurological development. Option A is correct because thyroxine deficiency causes this specific clinical syndrome. Thyroxine is a primary iodine-containing hormone essential for normal metabolic rate and growth. Congenital hypothyroidism can cause irreversible mental retardation if treatment is delayed. Newborn screening programs test hormone levels routinely to initiate early hormone replacement.
Early diagnosis and thyroxine supplementation allow normal physical and intellectual development in infants. Global iodine deficiency historically caused high rates of preventable cretinism in mountainous regions. Pediatricians monitor developmental milestones closely to detect congenital endocrine deficiencies early. Growth hormone deficiency causes short stature without the profound mental retardation seen here. Rickets involves vitamin D or calcium deficiency leading to soft and deformed bones. Parathyroid hormone regulates calcium homeostasis and does not cause this classic growth syndrome.
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