Abstract
Severe combined immunodeficiency (SCID) is an inborn error of immunity invariably resulting in mortality in infancy until managed by hematopoietic stem cell transplant (HSCT). We present an unusual case of SCID with a rare mutation involving the non-homologous end-joining 1 (NHEJ1) gene, where a haploidentical HSCT was carried out with modified conditioning and graft versus host prophylaxis regimen using proteasome inhibitor bortezomib with a successful outcome.