Deficiency of adenosine deaminase in the wasted mouse.

Wasted (wst) is a spontaneous mutation with autosomal recessive inheritance. Abnormally low levels of adenosine deaminase have been found in erythrocytes from the wasted mouse. Enzyme activity in wst/wst mice is reduced to 38% of that found in the erythrocytes from control mice, and the apparent Km for adenosine is reduced to 51% of control. These changes imply an alteration in the catalytic properties of the enzyme arising from a change in the primary structure of the protein. We postulate that wasted is a mutation in the structural gene for adenosine deaminase. In man, the autosomal recessive form of severe combined immunodeficiency is associated, in about one-third of cases, with a deficiency of adenosine deaminase. Wasted mice are immunodeficient, develop neurological abnormalities, and die soon after weaning. These features are shared with the human syndrome. We therefore further suggest that the wasted mouse is an animal model for this form of severe combined immunodeficiency that will have potential use in gene-therapy studies.