Atrophic Thymus in the First Case of the Interleukin 10 Receptor Beta Deficiency due to the Homozygous Large Deletion

Interleukin 10 (IL-10) and IL-10 receptor (IL-10R) deficiencies are among the primary immunodeficiency disorders (PIDs) caused by the loss-of-function mutations in the IL-10 or IL-10R encoding genes. IL-10 and IL-10R deficiencies are not prevalent and only a few cases have been reported in this regard so far. Among the patients, very early onset of the inflammatory bowel disease (VEO-IBD), usually during the infancy is the most common clinical manifestation of the disease. Almost all the patients come from the consanguineous families and present a similarly severe state of the disease. Therefore, in this study, the case of a 7-month-old girl, admitted with severe dehydration due to the watery diarrhea, fever, and repeated hospitalization with atrophic thymus was reported. According to the patients҆ past medical history, she came from a family with consanguineous marriage, and her sister also had died from the chronic diarrhea. She was nominated for the genetic examination to identify the underlying causes of her disease because of the normal laboratory analysis and standard immunological workup. Genetic evaluation by the whole exome sequencing revealed a homozygous mutation in the gene encoding the IL-10RB with a large deletion in the exons 3-7. Unfortunately, she deceased at the age of one before the hematopoietic stem cell transplantation.