Prenatal detection of a probable heterozygote for ADA deficiency and severe combined immunodeficiency disease using a microradioassay

Abstract
A pregnancy at risk for adenosine deaminase (EC 3.5.4.4) deficiency and severe combined immunodeficiency disease was investigated by assay of adenosine deaminase activity in cultured amniotic fluid cells using a microradioassay. A low-normal level of activity consistent with heterozygote status in the fetus was found and confirmed after birth by assay of red cell and fibroblast adenosine deaminase activities. The radioassay method may offer significant advantages in sensitivity and specificity over the standard spectrophotometric procedure.