A newborn screening program identifies an infant with congenital hypothyroidism. If treatment is not started promptly, which long-term outcome is most likely to occur?

• A. Progressive enlargement of skeletal muscles with normal intelligence
• B. Increased metabolic rate and accelerated bone maturation
• C. Severe impairment of physical growth and intellectual development
• D. Excessive secretion of digestive enzymes leading to malnutrition

Answer: (C)