Case report: Maternal engraftment of T-cells in a patient with Severe Combined Immunodeficiency due to DCLRE1C pathogenic variant - diagnostic and treatment challenges

Background

Severe combined immunodeficiency (SCID) is a rare but serious congenital condition caused by genetic defects that severely impair the development and function of T cells, B cells, and natural killer (NK) cells. Without early diagnosis and immune system reconstitution, SCID is usually fatal in infancy. The condition requires prompt recognition and hematopoietic stem cell transplantation (HSCT) to restore immune function. This report describes the first genetically confirmed case of SCID in Latvia - caused by a DCLRE1C gene pathogenic variant and diagnosed prior to the implementation of national newborn screening for SCID - complicated by disseminated tuberculosis following Bacillus Calmette-Guérin (BCG) vaccination.