Introduction: Microvillous inclusion disease (MVD) or microvillous atrophy disorder is a congenital disorder of the small intestinal epithelial cells that presents with persistent and severe diarrhea and it is characterized by enterocytes abnormalities . For these children, prognosis is generally poor due to metabolic acidosis with poor compensation. To our experiment, this disease is very rare in Iran and it is yet unreported, so we decided to report two consecutive siblings with the same disease from Iran. Report of Cases: Two siblings were born to healthy parents. Parents were cousins. Both siblings were hospitalized due to severe diarrhea starting shortly after breast feeding. The frequency of diarrhea in both cases was 10 to 17 times per day and their stools were loose and green. Histological studies of both siblings revealed duodenal mucosa with complete flattening of villi (total villous atrophy). Superficial lining cells showed atrophy. Crypts showed no hyperplasia, however it showed distortion and difference in size. By PAS staining and CD10 staining, a poorly developed brush border and typical inclusions were seen in apical boarder of enterocytes. Electron microscopy was performed for the second case and showed microvillous involution and inclusions in the apical part of the epithelial cells. Discussion: Microvillous congenital atrophy is a rare congenital disorder. Due to rareness of congenital microvillous atrophy (CMA), it is crucial to distinguish it from other diseases with persistent and severe diarrhea as soon as possible.
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