[Clinical and genetic analysis of a very early-onset inflammatory bowel disease type 28 child with atypical clinical manifestation].

Objective: To explore the clinical and genetic characteristics of a very early-onset inflammatory bowel disease (VEO-IBD) type 28 child with atypical clinical manifestations.

Methods: A VEO-IBD type 28 child with atypical clinical manifestations admitted to the Department of Neonatology, Children's Hospital Affiliated to Shandong University on November 5, 2021 was selected as the study subject. Clinical data of the child was collected. Peripheral venous blood samples of the child and his parents were collected for high-throughput sequencing. Candidate variants were verified by Sanger sequencing and bioinformatic analysis.

Results: The child, a 50-day-old male, had manifested bronchitis, ulcerative stomatitis, eczema and slightly loose stool. High-throughput sequencing revealed that he has harbored compound heterozygous variants of the IL-10RA gene, namely c.299T>G (p.V100G) and c.301C>T (p.R101W), which were inherited from his father and mother, respectively. Bioinformatic analysis showed that both variants have been recorded in the HGMD database, though the c.299T>G variant has not been included in the gnomAD, 1000 Genomes, ExAC and ESP6500 databases, while the c.301C>T variant has a low population frequency. Both variants were predicted to be deleterious by the online software including SIFT, PolyPhen-2 and Mutation Taster. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be pathogenic (PS3+PM2_Supporting+PP3).

Conclusion: The c.299T>G and c.301C>T variants of the IL-10RA gene probably underlay the VEO-IBD type 28 in this child. Above finding has expanded the phenotypic spectrum of VEO-IBD type 28 due to variants of the IL-10RA gene and provided a reference for the clinical diagnosis of this disease.