Intestinal microvillous dystrophy: a variant of microvillous inclusion disease or a new entity?

We report three patients with intestinal microvillous dystrophy, two of whom were siblings. The relatively delayed clinical presentation and the lack of classical microvillous inclusions distinguish these cases from the previously described microvillous inclusion disease (MVID). There appears to be an underrecognized spectrum of microvillous disorders leading to fatal intractable secretory diarrhea in infants. In our three cases the diagnosis was suggested by periodic acid-Schiff (PAS) and alkaline phosphatase preparations of a jejunal biopsy specimen showing thinning or absence of brush border staining, which was confirmed by electron microscopy. The latter showed poorly developed and haphazardly arranged microvilli with intracytoplasmic vesicular bodies but no true inclusions. As in MVID, the prognosis of intestinal microvillous dystrophy is poor. The occurrence of the disease in two siblings of consanguinous parents suggests an autosomal recessive inheritance, and like MVID, genetic counselling of affected families is essential.