Molecular Analysis of Hereditary Elliptocytosis With Reduced Protein 4.1 in the French Northern Alps

Abstract

4.1(-) hereditary elliptocytosis (HE) is a variety of elliptocytosis resulting from the reduction (heterozygosity) or the absence (homozygosity) of protein 4.1. It is nearly always encountered in its heterozygous form. It has been found among Caucasians and North Africans in a sporadic fashion. We report the study on nine family cases of 4.1(-) HE. They were recruited independently (to the exclusion of any other variety of HE) in a limited area around the city of Annecy (French Northern Alps). The mode of genetic transmission, as well as the clinical, morphologic, and protein phenotypes fully conformed to the classical description. Western blots ruled out the existence of any protein 4.1 species of abnormal size. No obvious DNA rearrangement was detectable in any of the nine families with three 4.1 cDNA probes covering the entire coding sequence and part of the flanking 5' and 3' untranslated sequences. On the basis of five polymorphic sites (Bgl II, 2; Pvu II, 3), we found five different haplotypes in normal members of the 4.1(-) families. 4.1(-) HE was associated with the most common haplotype in all the propositi. 4.1 mRNA was studied in four families. Dot-blot hybridization experiments and Northern blots failed to show any detectable change in three families. On the other hand, they showed a 2-kb deletion in the 4.1(-) messenger RNA 5'-moiety in one family. These findings emphasize the heterogeneity of 4.1(-) HE at the molecular level.