Variants of Lipolysis-Related Genes in Korean Patients with Very High Triglycerides

We investigated the prevalence and characteristics of variants of five lipolysis-related genes in Korean patients with very high triglycerides (TGs). Twenty-six patients with TG levels >885 mg/dL were selected from 13545 Korean subjects. Five candidate genes, LPL, APOC2, GPIHBP1, APOA5, and LMF1, were sequenced by targeted next-generation sequencing. Predictions of functional effects were performed and matched against public databases of variants. Ten rare variants of three genes were found in nine (34.6%) patients (three in LPL, four in APOA5, and three in LMF1). Five were novel and all variants were suspected of being disease-causing. Nine were heterozygous, and one (3.8%) had a homozygous rare variant of LPL. Six common variants of four genes were observed in 25 (96.2%) patients (one in LPL, one in GPIHBP1, two in APOA5, and two in LMF1). The c.G41T variant of GPIHBP1 and c.G533T variant of APOA5 were most frequent and found in 15 (57.7%) and 14 (53.8%) patients, respectively. Rare homozygous variants of the genes were very uncommon, while diverse rare heterozygous variants were commonly identified. Taken together, most study subjects may be manifesting the combined effects of rare heterozygous variants and common variants.

Polimorfismo S19W (Ser19Ter) de la APOA5 y su relación con la hipertrigliceridemia en una población de Colombia / S19W polymorphism (Ser19Ter) of APOA5 and its relationship with hypertriglyceridemia in a Colombian population

RESUMEN Introducción: Las enfermedades cardiovasculares (ECV) son responsables del 29,69% de las muertes en Colombia. Se ha encontrado la hipertrigliceridemia, en diversos estudios como factor de riesgo independiente para la ECV. El polimorfismo S19W (Ser19Ter) de la ApoA5 se ha asociado en algunas poblaciones con la hipertrigliceridemia. Sin embargo, en Colombia esto ha sido poco estudiado. Objetivo: Estimar la asociación entre el polimorfismo S19W y la hipertrigliceridemia en población colombiana. Metodología: Estudio tipo Corte Transversal, con 400 individuos provenientes de Bucaramanga, Colombia. Se cuantificó los TAG y se genotipificaron mediante la técnica de SNaPshot y mini secuenciación. Los resultados fueron analizados utilizando el software de análisis genético Arlequín 3.5.1.2. Resultados: El polimorfismo S19W (Ser19Ter) mostró tres perfiles, CC, GG y CG. El polimorfismo S19W se caracterizó tanto en afectados como en no afectados, mostrando que no existen diferencias significativas en esta distribución cuando se comparan los dos grupos. Discusión: Diversos mecanismos se han propuesto para sustentar la hipertrigliceridemia como un factor de riesgo para ECV, entre los que se cuenta la APOA5. El estudio comprobó que la población estudiada se encuentra en equilibrio de Hardy Weinberg y al genotipo CC como el más frecuente. Los genotipos GG y el GC presentaron valores significativos en el grupo de sujetos afectados, (p<0,01 y p=0,03; respectivamente). Se demostró la existencia de una estrecha relación entre el polimorfismo Ser19Trp y la hipertrigliceridemia (p<0,01). Conclusión: Se pudo demostrar la existencia de una relación entre el polimorfismo Ser19Trp de la Apo A5 con los niveles elevados de TAG (p<0,01).

ABSTRACT Introduction: Cardiovascular diseases (CVD) are responsible for 29.69% of the deaths in Colombia. Several studies have shown that hypertriglyceridemia is an independent risk factor for CVD. ApoA5 gene S19W (Ser19Ter) polymorphism has been associated with hypertriglyceridemia in some populations; however, their influence in Colombia is unknown. Objective: To determine the relationship between S19W polymorphism and hypertriglyceridemia in Colombian population. Methodology: Transversal crossover Studio, included a total of 400 individuals. TAG was quantified and genotyped using the technique SnapShot and mini sequencing. The results were analyzed using genetic analysis software Arlequin 3.5.1.2. Results: S19W (Ser19Ter) polymorphism showed three profiles, CC, GG and CG. The S19W polymorphism was characterized both affected and not affected. There wasn´t significant differences in the distribution when the two groups are compared. Discussion: Various mechanisms have been proposed to support hypertriglyceridemia as a risk factor for CVD, including the APOA5 counted. The study found that the study population is in Hardy Weinberg and CC genotype as the most frequent. The GG and GC genotypes showed significant values in the group of affected subjects (p = 0.002 and 0.03). It demonstrated the existence of a close relationship between the Ser19Trp polymorphism and hypertriglyceridemia (p<0,01). Conclusion: It was possible to demonstrate the existence of a relationship between polymorphism Ser19Trp of ApoA5 with elevated levels of TAG (p<0,01).

Impacto de la apolipoproteína A5 en el riesgo cardiovascular: Modulaciones genéticas y ambientales / Impact of apolipoprotein A5 on cardiovascular risk: Genetic and environmental modulation

Triglyceride concentrations are an independent risk factor for coronary heart disease. Apolipoprotein A5 gene (APOA5) has an important role determining triglyceride metabolism and it is a potential cardiovascular risk. However the mechanisms for these actions are not well-known. Despite the different allelic frequency of its major polymorphisms in different populations, multiple studies have shown consistent associations between these variants and fasting triglycerides. Variations in the APOA5 gene have also been associated with postprandial triglycerides, as well as with different sizes of lipoproteins and other markers. Moreover, some of the APOA5 gene variants have been associated with ischemic heart disease, stroke, and carotid intima media thickness, although the references on this issue are scanty and contradictory. This may be due to the presence of gene-environment interactions that have been poorly studied until now. Among the few studies that have examined the infuence of environmental factors on possible genetic variations, the most important are those that contemplate possible gene-diet interactions. However, the evidence is still scarce and more research is required in the feld of nutrigenomics. To understand the impact of this gene on cardiovascular disease, we review the genetic functionality and variability of APOA5, its associations with intermediate and fnal phenotypes and gene-environment interactions detected.