## Overview Severe combined immunodeficiency (SCID) is a lethal autosomal recessive disorder of Arabian foals (and breeds carrying Arabian bloodlines). A mutation in the DNA-dependent protein kinase catalytic subunit gene prevents development of functional T and B lymphocytes. Foals are normal at birth but develop fatal infections once maternal antibodies wane, usually between 2 and 5 months of age. Death typically occurs by 5 months. ## Causes Inherited DNA-PKcs mutation. ## Diagnosis Lymphopenia, absence of IgM, and DNA testing. Affected foals and carriers can be identified by genetic test. ## Treatment None effective. Supportive care only. Euthanasia is humane once infections begin. ## Recovery and Prognosis Fatal. ## Prevention Genetic testing of breeding Arabians to avoid carrier-to-carrier matings.
recurrent infections starting at 2 to 5 months; pneumonia; diarrhea; failure to thrive; death by 5 months; no response to antimicrobials
## Overview Severe combined immunodeficiency (SCID) is a lethal autosomal recessive disorder of Arabian foals (and breeds carrying Arabian bloodlines). A mutation in the DNA-dependent protein kinase catalytic subunit gene prevents development of functional T and B lymphocytes. Foals are normal at birth but develop fatal infections once maternal antibodies wane, usually between 2 and 5 months of age. Death typically occurs by 5 months. ## Causes Inherited DNA-PKcs mutation. ## Diagnosis Lymphopenia, absence of IgM, and DNA testing. Affected foals and carriers can be identified by genetic test. ## Treatment None effective. Supportive care only. Euthanasia is humane once infections begin. ## Recovery and Prognosis Fatal. ## Prevention Genetic testing of breeding Arabians to avoid carrier-to-carrier matings.
recurrent infections starting at 2 to 5 months; pneumonia; diarrhea; failure to thrive; death by 5 months; no response to antimicrobials