Key result
Genetic screening of 4 Saudi families with familial hypercholesterolemia identified 1 novel frameshift and 3 known missense variants in the LDLR gene linked to severe clinical phenotypes.
Why the study?
FH is a leading cause of coronary artery disease, and identifying genetic defects in index patients and first-degree relatives helps understand genotype-phenotype correlations.
Observational
Identification of a novel LDLR frameshift variant expands the genetic spectrum of familial hypercholesterolemia and highlights the importance of cascade screening in high-risk families.
Supports targeted genetic testing in high-risk Saudi families; extends LDLR variant spectrum but leaves open validation for routine cascade screening.
BACKGROUND: Familial hypercholesterolemia (FH) is a common illness mainly caused by variants occurring in the low-density lipoprotein receptor (LDLR) gene. FH is a leading cause of coronary artery disease. OBJECTIVE: This study aims to determine genetic defect(s) in homozygous and heterozygous FH index patients and their first-degree blood relatives and understand the genotype-phenotype correlation. METHODS: This study employed the genetic screening of FH-related genes by next-generation sequencing and cascade screening by capillary sequencing. RESULTS: We identified the presence of a novel frameshift variant [c.335_336insCGAG, p.(F114Rfs*17)] and three known missense variants [c.622G>A, p.(E208K)], [c.1474G>A, p.(D492N)], [c.1429G>A, p.(D477N)] in the LDLR gene of four unrelated Saudi families with FH. In proband 1, a nonsense variant c.1421C>G, p.(S474*) was also detected at exon 9 of the lipoprotein lipase gene. The segregation arrangement of the identified variants corresponded with the clinical characteristics. In this study, all the detected variants were confined in the ligand-binding domain and epidermal growth factor (EGF)-precursor homology domain of the LDLR protein, which portrayed severe clinical phenotypes of FH. Moreover, these LDLR variants were in a highly conserved residue of the proteins. CONCLUSION: In addition to the finding of the novel variant in the LDLR gene that extends the spectrum of variants causing FH, the results of this study also support the need for diagnostic screening and cascade genetic testing of this high-risk condition and to understand the genotype-phenotype correlation, which could lead to better prevention of coronary artery disease.
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Alnouri et al. (2022) conducted an observational in Familial hypercholesterolemia. LDLR gene variants was evaluated on Identification of genetic defects and genotype-phenotype correlation. Genetic screening of 4 Saudi families with familial hypercholesterolemia identified 1 novel frameshift and 3 known missense variants in the LDLR gene linked to severe clinical phenotypes.
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