Clinical Reasoning: A 12-month-old child with hypotonia and developmental delays.

A 12-month-old girl was referred to the pediatric neuromuscular clinic for evaluation of hypotonia and weakness based on concerns from her pediatrician. The patient was born at term following an uncomplicated pregnancy, but developed failure to thrive and gross motor delays (unable to lift head in prone position) around 4 months of age. By 7 months of age, she began having episodes of bradypnea, tiring during feeds, acrocyanosis, and perioral cyanosis during periods of agitation.