A 9-month-old boy presents with failure to thrive, developmental delay, and recurrent seizures. Physical examination reveals hypothermia (36.2°C), sparse kinky hair, and skin laxity. Vital signs show HR 92/min, RR 22/min, SpO2 98% on room air. Laboratory studies demonstrate serum copper 45 μg/dL (normal 70-150) and ceruloplasmin 8 mg/dL (normal 20-40). Bone radiographs show periosteal spurs consistent with connective tissue involvement. There is no hepatomegaly. Deficiency of which enzyme most directly causes his connective tissue abnormalities?
- A)Dopamine beta hydroxylase only
- B)Tyrosinase only
- C)Ornithine transcarbamylase
- D)Prolyl hydroxylase
- E)Lysyl oxidaseGABARITO
Explicação
Menkes disease is caused by defective copper transport, leading to low copper availability for copper dependent enzymes. Lysyl oxidase requires copper for collagen and elastin cross linking, so deficiency causes connective tissue and vascular abnormalities. Ki... Ver explicação completa e trilha adaptativa →