SLC10A2 deficiency-induced congenital chronic bile acid diarrhea and stunting.

Background: Diarrhea is a common occurrence in children below the age of 5 years. In chronic cases, it induces malnutrition that severely stunts growth. Bile acid diarrhea (BAD), caused by malabsorption of bile acid (BA), is a rare form of chronic diarrhea seldom observed in pediatric patients. Here, we present a clinical report on a novel case of chronic BAD, with severe stunting in an infant, induced by a homozygous mutation of SLC10A2.

Methods: We performed DNA extraction, whole-exome sequencing analysis, and mutation analysis of SLC10A2 to obtain genetic data on the patient. We subsequently analyzed the patient's clinical and genetic data.

Results: The patient's clinical manifestations were chronic diarrhea with increased BAs in the feces and extreme stunting, which was diagnosed as BAD. A homozygous mutation of SLC10A2 at the c.313T>C (rs201206937) site was detected.

Conclusion: Our report reveals the youngest case illustrating the characteristics of BAD induced by genetic variant at 313T>C, and the second case entailing a clear association between a SLC10A2 genetic mutation and the onset of BAD. Our findings expand the mutant spectrum of the SLC10A2 gene and contribute to the refinement of the genotype-phenotype mapping of severe stunting induced by pediatric BAD. Moreover, they highlight the value of molecular genetic screening for diagnosing BAD in young patients.