The Missing ApoE Allele
The human apoE gene (APOE, GenBank accession AF261279) shows a common polymorphism, with the three 2, 3 and 4 alleles resulting from the haplotypes of two C→T SNPs. However, whereas the three common T-T, T-C and C-C haplotypes corresponding to the 2, 3 and 4 alleles are well known, the last C-T haplotype (GenBank accession AY077451), encoding a fourth apoE allele, has rarely been reported. We detected this fourth allele in a Caucasian patient with motor neuron disease (MND). According to the literature we refer to this allele as 3r. Although several explanations may be proposed for its formation, the existence of this fourth allele is consistent with the evolutionary hypothesis generally accepted for the apoE alleles. The rarity and physiological role of 3r remains to be explained, and requires further investigation.
Document Type: Research Article
Affiliations: 1: Laboratory of Geriatrics and Gerontology, Department of Research, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo (FG), Italy 2: Institute of Neurology, Catholic University School of Medicine, Rome, Italy 3: Institute of Neurobiology and Molecular Medicine, CNR-ARTOV, Rome, Italy 4: Laboratory of Genetics, Department of Research, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo (FG), Italy 5: Department of Geriatrics, Center for Aging Brain, Memory Unit, University of Bari, Bari, Italy
Publication date: July 1, 2007