A novel 268 kb deletion combined with a splicing variant in IL7R causes of severe combined immunodeficiency in a Chinese family: a case report.

Severe combined immunodeficiency (SCID) is a group of fatal primary immunodeficiencies characterized by the severe impairment of T-cell differentiation. IL7R deficiency is a rare form of SCID that usually presents in the first months of life with severe and opportunistic infections, failure to thrive, and a high risk of mortality unless treated. Although recent improvements in early diagnosis have been achieved through newborn screening, few IL7R-related SCID patients had been reported in the Chinese population. Here, we retrospectively analyzed a case of SCID in a 5-month-old girl with symptoms, including severe T-cell depletion, recurrent fever, oral ulcers, pneumonia, hepatosplenomegaly, bone marrow hemophagocytosis, and bacterial and viral infections. Whole-exome sequencing (WES), quantitative PCR (qPCR), and chromosome microarray analysis (CMA) were performed to identify the patient's genetic etiology. We identified a 268 kb deletion and a splicing variant, c.221 + 1G > A, in the proband. These two variants of IL7R were inherited from the father and mother. To our knowledge, this is the first report of whole IL7R gene deletion in combination with a pathogenic splicing variant in a patient with SCID. This deletion also expands the pathogenic variation spectrum of SCID caused by IL7R. The incorporation of exome-based copy number variant analysis makes WES a powerful molecular diagnostic technique for the clinical diagnosis of pediatric patients. © 2023. The Author(s).

Citation

Lulu Yan, Yan He, Yuxin Zhang, Yingwen Liu, Limin Xu, Chunxiao Han, Yudan Zhao, Haibo Li. A novel 268 kb deletion combined with a splicing variant in IL7R causes of severe combined immunodeficiency in a Chinese family: a case report. BMC medical genomics. 2023 Dec 11;16(1):323

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PMID: 38082310

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