Immunodeficiency-19 (IMD19) is an autosomal recessive form of severe combined immunodeficiency (SCID) characterized by onset in early infancy of recurrent bacterial, viral, and fungal infections. Patients usually have chronic diarrhea, recurrent respiratory infections, and failure to thrive. Immunologic work-up shows a T cell-negative, B cell-positive, natural killer (NK) cell-positive phenotype. The disorder is lethal in early childhood without bone marrow transplantation. [From OMIM]