Haplotype analysis of the human apolipoprotein B mutation associated with familial defective apolipoprotein B100.
 Haplotype analysis was conducted on the mutant allele of 14 unrelated subjects heterozygous for a mutation in the codon for amino acid 3500 of human apolipoprotein B100.
 This mutation is associated with defective binding of low-density lipoprotein to the low-density lipoprotein receptor and with moderate hypercholesterolemia.
 Ten markers were used for haplotyping: eight diallelic markers within the structural gene and two hypervariable loci flanking the gene.
 Seven of eight unequivocally deduced haplotypes were identical, and one revealed only a minor difference at one of the hypervariable loci.
 The genotypes of the six other affected subjects were consistent with this same assigned haplotype.
 These data are consistent with a common ancestral chromosome and provide no evidence for a recurrent mutation at this potentially hypermutable CG dinucleotide, despite the fact that this mutation is not rare.
