A study of familial hypercholesterolemia in Iceland using RFLPs

We have studied 17 unrelated families from Iceland who have familial hypercholesterolemia (FH), using three different restriction fragment length polymorphisms (RFLPs) of the LDL receptor gene. In one family FH was caused by a 2 kb deletion in the LDL receptor gene in the region of exons 9 to 10. The PvuII (intron 15), Ncol (exon 18), and ApaLl (intron 15) RFLPs were used to determine the haplotypes associated with the defective LDL receptor gene in Iceland. Genotypes were determined in 77 subjects from these 17 families, both FH and non-FH. A rare new Ncol RFLP was detected in three subjects. Among the patients, at least four different haplotypes were observed indicating that FH in Iceland is caused by at least four different mutations and is a heterogeneous disease, even in the small, geographically isolated population of Iceland.