Red blood cell enzymes in the diagnosis of genetic disease

Erythrocytes are uniform cells which contain only those proteins that are synthesized during the reticulocyte stage. The relationship of red cell enzymes to gene dosage and gene expression enables the use of red cell enzyme assays to determine the presence or absence of gene defects causing enzyme deficiencies leading to various metabolic diseases; in addition, the mode of inheritance of these defects can frequently be ascertained by analyzing red cell enzymes. However, indirect evidence favoring other enzyme deficiency states can sometimes be obtained from a study of red cell enzyme activities, because apparent enzyme deficiencies may result from the accumulation of inhibitory metabolites formed due to an enzyme deficiency in other tissues. The polymorphic expression of many red cell enzymes lends itself to biochemical analysis which can produce highly accurate and specific diagnostic information.