Analysis of a child with Very early onset inflammatory bowel disease due to compound heterozygous variants of IL10RA and DUOX2 genes

Abstract

To explore the genetic basis of a child with Very early onset inflammatory bowel disease (VEOIBD). A female child who had presented at the Children's Hospital of Fudan University on May 23, 2018 due to occurrence of diarrhea and fever 6 days after birth was selected as the study subject. Clinical data of the child was collected. Family-based whole-exome sequencing (WES) was carried out. Candidate variant was verified by Sanger sequencing and PCR of the patient and her parents. The child had developed the symptoms 6 days after birth, with main manifestations including diarrhea, fever, failure to thrive, rectovestibular fistula and hypothyroidism. An enterostomy was performed at the age of 3.5 months due to severe intestinal adhesion and obstruction. Based on her clinical manifestations, colonoscopic finding, and results of biopsies, she was diagnosed with VEOIBD in conjunct with congenital hypothyroidism. Replacement treatment of levothyroxine was given since one month of age. Family-based WES revealed that the child has harbored compound heterozygous variants of the DUOX2 gene, namely c.2654G>T (p.R885L) and c.505C>T (p.R169W), in addition with a heterozygous c.301C>T (p.R101W) variant of the IL10RA gene. Re-analysis of the WES data revealed that the patient also had a 333 bp deletion spanning exon 1 of the IL10RA gene (Chr11: 117857034_117857366). For patients with VEOIBD, genetic testing is recommended. Presence of additional DUOX2 gene variants might have exacerbated the clinical symptoms in this patient. Above finding has facilitated genetic counseling and prenatal diagnosis for this family, and raised clinicians' awareness of this rare disease.