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

Front Pediatr. 2021 Dec 2;9:731716. doi: 10.3389/fped.2021.731716.

PMID: 34926337

Jianli Zhou, Yuzhen Zhao, Xia Qian

Highlights: This article reports a case of novel variants in the SI gene that caused CSID. This report provides valuable information for the clinical field, especially in China.

Abstract

Background: Congenital sucrase-isomaltase deficiency (CSID) is an autosomal recessive hereditary condition characterized by disaccharide maldigestion and is linked to a mutation in the sucrase-isomaltase (SI) gene. CSID cases are not common in China or around the world, but they are gradually being found and reported.

Case Presentation: We present a case of a 14-month-old boy who was admitted for chronic diarrhea and presented with failure to thrive that began following food diversification. To find mutations in this patient's genome, we performed whole-exome sequencing (WES). WES identified two new heterozygous mutations in the SI gene: c.2626C > T (p.Q876*) and c.2872C > T (p.R958C), both of which were confirmed by Sanger DNA sequencing. The patient's diarrhea was controlled, and he began to gain weight, thanks to a strict sucrose and starch-restricted diet.

Conclusions: We present a case of CSID caused by novel SI gene variants. This report is extremely useful in the clinical field, particularly in China.

Keywords: case report, congenital, gene, mutation, sucrase-isomaltase deficiency