A 6-year-old boy with failure to thrive presents with fat-soluble vitamin deficiencies (A, D, E, K), steatorrhea, and hepatomegaly. Vital signs show HR 102/min, BP 95/60 mmHg, and normal temperature. Laboratory testing reveals total cholesterol 450 mg/dL, triglycerides 680 mg/dL, and prolonged PT/INR. Abdominal ultrasound shows hepatomegaly without cirrhosis. He denies recent infections. Electron microscopy of jejunal biopsy demonstrates lipid droplet accumulation in enterocytes. Which gene mutation most likely explains this presentation?
- A)LIPE (hormone-sensitive lipase)
- B)MTP (microsomal triglyceride transfer protein)GABARITO
- C)LDLR (LDL receptor)
- D)LIPC (hepatic lipase)
- E)APOB (apolipoprotein B)
Explicação
This is abetalipoproteinemia, caused by MTP mutations. MTP is essential for lipoprotein assembly in both intestinal and hepatic cells. Without it, chylomicron and VLDL assembly fail, causing lipid accumulation in enterocytes, malabsorption, and fat-soluble vit... Ver explicação completa e trilha adaptativa →