Congenital diarrhea in a newborn infant: A case report

BACKGROUND: Microvillus inclusion disease (MVID) is a rare autosomal recessive cause of severe congenital diarrhea with significant morbidity and mortality. Definitive treatment involves bowel transplant. The diagnosis of this condition can be challenging and a few genetic panels are available for the identification of the most common mutations. We present the case of an infant with MVID due to a mutation not reported in the literature before. CASE SUMMARY: We report the case of an infant transferred to our institution with severe diarrhea of unknown etiology, failure to thrive, and significant metabolic derangements. An extensive work-up including stool studies for common gastrointestinal pathogens, abdominal ultrasound, esophagogastroduodenoscopy with duodenal biopsy and flexible sigmoidoscopy failed to reveal a diagnosis. Multiple dietary and formula regimens were introduced but all resulted in voluminous diarrhea. She remained on total parenteral nutrition (TPN) for the duration of her hospital stay. Genetic testing was done and she was subsequently found to have a novel mutation in the MYO5B gene [homozygous mutation for MYO5B c.1462del, p. (Ile488Leufs*93)] giving us the diagnosis of MVID. She remains on TPN while awaiting bowel transplant at the time of the compilation of this case report. CONCLUSION: We report a novel mutation involved in MVID and highlight the importance of considering this disease when faced with a newborn presenting with life threatening diarrhea. At the time of this publication, 232 allelic variations of this gene (MIM#606540) exist in National Center for Biotechnology Information’s database. Our patient’s mutation has not been reported in literature as a cause of MVID.