Partial deficiency of protein 4.1 in hereditary elliptocytosis.

Protein 4.1, an important component of the red cell membrane skeleton, was quantitated relative to protein 3 after sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of membranes isolated from red cells of members of 14 kindreds with hereditary elliptocytosis (HE) who reside in South Africa. A partial deficiency of protein 4.1 (mean 30% reduction) was inherited in autosomal dominant fashion in five white kindreds giving a frequency of 0.36 of HE families studied. Immunoblots of membrane proteins separated by SDS-PAGE and probed with a monoclonal antibody to protein 4.1 did not reveal any proteolytic fragments in the 4.1-deficient subjects that could account for the reduction of this protein. These studies draw attention to the relatively high frequency of this condition as a cause of HE in white subjects in this country.