A 3-year-old boy with consanguineous parents presents with failure to thrive, developmental delay, and progressive ataxia with nystagmus. Vital signs show HR 92/min, RR 20/min, BP 95/60 mmHg, temp 37°C. Serum cholestanol is markedly elevated at 18 mg/dL (normal <1 mg/dL) with abnormal cholesterol metabolism. MRI shows cerebellar atrophy. He lacks xanthomas or peripheral neuropathy. Which enzyme is most likely deficient?
- A)ABCA1 transporter
- B)Lecithin-cholesterol acyltransferase (LCAT)
- C)Lipoprotein lipase
- D)Cholesterol 7α-hydroxylase
- E)Sterol 27-hydroxylaseGABARITO
Explicação
This presentation is consistent with cerebrotendinous xanthomatosis (CTX), caused by sterol 27-hydroxylase deficiency. This enzyme catalyzes the first step of cholestanol catabolism to bile acids. Cholestanol accumulates in the brain, causing progressive neuro... Ver explicação completa e trilha adaptativa →