An 87 bp deletion in exon 5 of the LDL receptor gene in a mother and her son with familial hypercholesterolemia.

DNA analysis of the low density lipoprotein receptor (LDLR) gene was performed in two persons with familial hypercholesterolemia (FH). Southern blot experiments indicated the heterozygous loss of an EcoRI site in exon 5 of the LDLR gene. Upon amplification and sequencing of exon 5 in both probands, an 87-bp deletion in a heterozygous state could be evaluated. This is a novel mutation, most probably leading to the formation of a nonfunctional LDLR. Analysis of the deletion breakpoints revealed the presence of a six-base-pair consensus sequence 5'TGA/GA/GG/TA/C3', which is characteristic of small deletions in different genetic defects.