A de novo mutation in /ITPR3/ causes combined immunodeficiency

This study reports two unrelated patients with a combined immunodeficiency. Whole-exome sequencing of both patients, their healthy parents and siblings identified in both families a /de novo/ missense variant in /ITPR3/ (NM_002224.3:c.7570C>T, p.Arg2524Cys). While the mRNA level in patients remained the same as in healthy siblings and controls, the level of protein expression was diminished. It was also shown that the ITPR3 heterozygous p.Arg2524Cys mutation impairs calcium flux function in dermal fibroblast of one patient and in a knock-in Jurkat T cell line.