Describe the difference between osmotic and secretory diarrhea:
Osmotic diarrheas are due to inability to absorb. They resolve with bowel rest.
Mutations in these genes cause what enteropathy?
SARIB: Chylomicron retention (Anderson)
MYO5B: Microvillus inclusion disease
EpCAM: Tufting enteropathy
SLCA7: Lysinuric protein intolerance
NEUROG3: Enteroendocrine cell dysplasia
A. What are the ultrastructural findings in microvillus inclusion disease?
B. On a cellular level, what's the mechanism of disease?
C. What will PAS stain?
A. Stubby microvilli and apical vescicles containing microvilli.
B. Absent ability to integrate myosin 5b to the membrane (?), thanks to MYO5B gene mutation.
C. Nothing. PAS should stain a normal brush border, which you won't see anymore.
How does abetalipoproteinemia differ from chylomicron retention disease?