[Analysis of clinical phenotype and variant of RAG1 gene in a child with B-cell-negative Severe Combined Immunodeficiency].

OBJECTIVE

To report on a child with B-cell-negative severe combined immunodeficiency (B-SCID) manifesting as fulminant myocarditis and carry out genetic testing for her.

METHODS

A child with B-SCID who presented at Fujian Maternity and Child Health Care Hospital on January 31, 2021 was selected as the subject. Whole exome sequencing was carried out for her. Candidate variant was verified by Sanger sequencing.

RESULTS

The female infant had developed recurrent skin and lung infections soon after birth, and was admitted due to fulminant myocarditis. Serological examination has disclosed a remarkable reduction in immunoglobulins. Flow cytometric analysis revealed that her peripheral blood T and B lymphocytes and NK cells were significantly reduced. Whole exome sequencing revealed that she has harbored a homozygous c.C3007T (p.Q1003X) nonsense variant of the RAG1 gene, for which both of her parents were heterozygous carriers. The variant has not been recorded in normal population databases. Based on the guidelines from the American College of Medical Genetics and Genomics, the variant was predicted to be pathogenic.

CONCLUSION

A case of RAG1 gene associated B-SCID has been diagnosed. Above finding has enriched the spectrum of RAG1 gene variants and enabled early diagnosis and intervention of the disease.