PRKDC and severe combined immunodeficiency: An autosomal SCID caused by mutation of the DNA-PK gene encoding DNA-dependent protein kinase was diagnosed in Jack Russell Terriers; X-linked SCID (X-SCID), caused by two different mutations of the IL2RG gene (encoding interleukin 2 receptor subunit gamma) specific to the Basset Hound and Cardigan Welsh Corgi breeds were reviewed by Perryman (2004).