Two Novel Mutations in the Gene Associated With Congenital Sucrase-Isomaltase Deficiency: A Case Report in China.

Congenital sucrase-isomaltase deficiency (CSID) is an autosomal recessive inherited disease that leads to the maldigestion of disaccharides and is associated with mutation of the sucrase-isomaltase () gene. Cases of CSID are not very prevalent in China or worldwide but are gradually being identified and reported. We report a case involving a 14-month-old male who presented with failure to thrive that had begun after food diversification and was admitted for chronic diarrhea. We used a whole-exome sequencing (WES) approach to identify mutations in this patient's genome. WES revealed two novel heterozygous mutations in the gene, c.2626C > T (p.Q876) and c.2872C > T (p.R958C), which were confirmed by Sanger DNA sequencing. With a strict sucrose- and starch-restricted diet, the patient's diarrhea was resolved, and he began to gain weight. We report a case of novel variants in the gene that caused CSID. This report provides valuable information for the clinical field, especially in China.