Analysis of low density lipoprotein receptor gene mutations and microsatellite haplotypes in Greek FH heterozygous children: six independent ancestors account for 60% of probands

Abstract

This study reports the characterization of 60% of low density lipoprotein receptor (LDLR) gene mutations in 150 unrelated Greek familial hypercholesterolaemia (FH) heterozygous children by the analysis of six LDLR gene mutations. The linkage disequilibrium of two polymorphic microsatellites (D19S394 and D19S221) flanking the LDLR gene on chromosome 19 to the four most common mutations strongly suggests that each mutation is identical-by-descent in the probands included in this study (this is also supported by the geographical distribution of FH families with these mutations throughout Greece) and permits an estimation of the number of generations from a common ancestor for each mutation. The characterization of 60% of LDLR mutations in a representative sample of Greek FH heterozygotes provides a basis for the diagnosis of FH through DNA analysis in Greece, by using single-strand conformation polymorphism analysis followed by allele-specific oligonucleotide hybridization (exon 6 mutations) or restriction endonuclease analysis (C152R, V408M). A rapid diagnostic assay positive for the mutation has been developed for the most common mutation, G528D. The application of simple DNA diagnostic assays for LDLR mutation analysis are appropriate for the early identification of FH heterozygotes in Greece and are useful for the primary prevention of coronary artery disease.

Clinical Expression of Familial Hypercholesterolemia in Clusters of Mutations of the LDL Receptor Gene That Cause a Receptor-Defective or Receptor-Negative Phenotype

“…Interestingly, G528D is fairly common in Greece, where it accounts for 23% of unrelated FH heterozygotes and shows 91% linkage disequilibrium with a single D19S394 microsatellite allele (257 bp). 51 In our series, all patients carrying the G528D mutation share the same intragenic haplotype, but the mutation was found to be linked with 4 different alleles of the D19S394 microsatellite.…”

Characterization and geographic distribution of the low density lipoprotein receptor (LDLR) gene mutations in northwestern Greece

“…The 73 FH patients were screened for all previously identified LDLR gene mutations in the Greek population (Traeger-Synodinos et al, 1998;Miltiadous et al, 2000) using restriction isotyping. Twenty-seven patients did not possess any of the known LDLR gene mutations.…”

“…PCR was carried out using an MJR PTC -100 thermal cycler. Restriction isotyping was used for detecting previously described LDLR gene mutations (Traeger-Synodinos et al, 1998;Miltiadous et al, 2000). Automated sequencing was performed using the Applied Biosystems "Big Dye Terminator Cycle Sequencing Ready Reaction Kit" as instructed by the manufacturer (Applied Biosystems).…”

“…The clinical diagnosis is only confirmed by the identification of the mutation in the LDLR gene. However, only few studies in Greece (Traeger-Synodinos et al, 1998;Mavroidis et al, 1997;Hobbs et al, 1992;Miltiadous et al, 2000) have to date, characterized mutations of the LDL receptor gene and until recently there has been no systematic analysis of the mutations causing FH in the Greek population, especially in Northwestern Greece. Knowledge of the mutations in the LDLR gene which predominate in certain regions helps to confirm the clinical diagnosis and also to identify younger affected members in a known affected family or a new FH proband originating from a particular region.…”

Rapid screening of the LDL receptor point mutation FH-Genoa/Palermo

“…In Southern Italy, one of the authors (B.S., unpublished data) has identified a cluster of 10 families with the same mutation; this finding and the present study suggest that the FH G528D represents a prominent cluster of FH mutation in Southern Italy .It is also interesting that in 5 of newly discovered FH Genoa/ Palermo Sicilian families and in 2 of FH Genoa/Palermo families from Southern Italy the D19S394-259-bp microsatellite was found co-segregating with the mutation; in addition, the 263-bp microsatellite was found associated with 6 families from Southern Italy and 2 families from Sicily and the 243-bp microsatellite in 2 families from Southern Italy and in 11 families in Sicily. This mutation has been recently described as one of the most frequent mutations in Greece (Traeger-Synodinos et al,1998) accounting for the 22.7% of LDL receptor mutations in that country; in 91% of the Greek FH Genoa/Palermo families the D19S394-259-bp microsatellite co-segregated with the mutation (Day et al,1997;Lee et al,1998) . Since Southern Italy and Sicily have been in the past a Greek colony one might speculate about a common origin of this mutation even if it is very difficult to trace and date the recombination events.…”