Blood cell phosphofructokinase in Down's syndrome

Summary Measurement of erythrocyte phosphofructokinase (PFK) activity in Down's syndrome failed to confirm the nearly 50% increase reported by others. An increase of 29% was found, while leukocyte PFK activity was normal. Erythrocyte PFK differs immunochemically from platelet and leukocyte PFK, and the enzyme is probably genetically heterogeneous; therefore, it remains possible that a structural gene for erythrocyte PFK is present on chromosome 21.This work was supported in part by grant FR-05355 (M.M.C.) and grant AM-12588 (R.B.L.) from the National Institutes of Health. Dr. Layzer is the recipient of Career Development Award NB-35310 from the National Institute of Neurological Diseases and Stroke.