We studied a French kindred with hereditary elliptocytosis associated with a spectrin variant (spectrin LePuy) containing a β-spectrin chain that is truncated at its C terminus (Dhermy, D., Lecomte, M., Garbarz, M., Bournier, O., Galand, C., Gautero, H., Feo, C., Alloisio, N., Delaunay, J., and Boivin, P. (1982) J. Clin. Invest. 70, 707-715). The structure of the 3′ end of the β-spectrin gene, the region encoding the C terminus of β-spectrin, was determined. Nucleotide sequencing of amplified genomic DNA revealed a mutation at position +4 (A → G) of the 5′ donor consensus splice site of the intron following the third-to-last exon (exon X) in one β-spectrin allele of a heterozygous patient. Agarose gel electrophoresis of polymerase chain reaction-amplified cDNA revealed an extra band of lower molecular weight, suggesting that the short-ened β-spectrin chain of spectrin LePuy arises from aberrant mRNA splicing. Nucleotide sequencing of the shorter cDNA amplification product revealed that the sequences encoding exon X were absent. Southern blotting of cDNA amplification products confirmed this result. The skipping of exon X causes a shift in the normal reading frame resulting in the encoding of a new amino acid sequence at the C terminus of the mutant β-spectrin chain. A new in-frame stop codon is encountered following a single residue of this novel sequence.26623151541515
