Microvillus Inclusion Disease: A Rare Mutation of STX3 in Exon 9 Causing Fatal Congenital Diarrheal Disease

Abstract

Inherited diarrheal disorders cause serious morbidity resulting in dependence on intensive care and parenteral nutrition. Microvillus inclusion disease (MVID) has been classically described and results from mutations in the gene coding myosin Vb, which is responsible for enterocyte polarization. Newer reports of mutations resulting in truncated syntaxin 3 (STX3) and Munc18-2 (STXBP2) proteins have been elucidated as causative. To date, five cases of STX3 abnormalities resulting in MVID have been described. We report an infant who presented with congenital diarrhea and was determined to have a rare mutation of STX3. This new finding would be beneficial in future functional genotype–phenotype correlation studies.

CODE Think! Rare Mutations of STX3 Causing Microvillus Inclusion Disease

“…This would support the hypothesis as in the last case report that the Indian community is highly endogamous. 2 Hence, we seek to remind intensivists to contemplate CODE as one of the major reasons for early/severe infantile diarrhea and to appraise NGS as a potential diagnostic tool.…”

“…We previously reported an infant with severe malnutrition and failure to thrive. 2 The infant succumbed to the disease after weeks of intensive care having received trials of elemental amino acid formula, Ross Carbohydrate Free (þfructose) diet trials, and parenteral nutrition. Clinical exome by next-generation sequencing (NGS) revealed a pathogenic homozygous, one base pair insertion in exon 9 of the STX3 gene resulting in microvillus inclusion disease (MVID).…”