Spectrum of LDLR gene mutations, including a novel mutation causing familial hypercholesterolaemia, in North-western Greece.

BACKGROUND: Familial Hypercholesterolaemia (FH) is a clinical syndrome characterised by elevated serum low-density lipoprotein (LDL) cholesterol, by tendon xanthomata and clinical manifestations of ischaemic heart disease in early life. Typically, it results from mutations in the low-density lipoprotein receptor (LDLR) gene. Furthermore, there are 3 additional genetic disorders that cause clinical syndromes that mimic FH. These are: 1) familial ligand-defective apolipoprotein (apo)-B (FLDH), 2) familial hypercholesterolaemia type 3 (FH3) and 3) autosomal recessive hypercholesterolaemia (ARH). The aim of this study was to elaborate the impact of the above genetic disorders in Greek patients with a clinical diagnosis of FH. METHODS: In this study, we assessed the contribution of the LDLR, Apo B, ARH and PCSK9 genes in the expression of FH in North-western Greece. Two hundred and fifty-four (254) probands with a clinical diagnosis of FH were included in the study. RESULTS: One hundred and sixty-nine (169) patients had one of the following LDLR gene mutations: 81T>G, 1775G>A, 517T>C, 858C>A, 1352T>C, 1285G>A, 761A>C, 1195G>A, 1646G>A and a deletion mutation g.387-410del24 in exon 4. We sequenced the Apo B, ARH and PCSK9 genes in 40, randomly selected patients, from the 85 patients with no identified LDLR gene defects. In these 40, randomly selected patients, with the exception of benign single nucleotide polymorphisms, no functional mutations were identified for all the above mentioned sequenced genes. CONCLUSION: Our results reveal substantial genetic heterogeneity for FH in North-western Greece with at least ten LDLR gene mutations present in the study population. One of these mutations although quite rare is reported here for the first time in the scientific literature. The detection of these mutations is important as they may be used to design multiplex detection assays for large scale population screening programmes to facilitate primary and secondary prevention of cardiovascular disease in the region. Finally, ARH, Apo B and PCSK9 gene defects were excluded from causing FH in a subgroup of the study population indicating that other yet unrecognized genes may be involved in causing the clinical feature of FH, and/or that large scale deletions/duplications evaded the applied mutation detection techniques of this study.

Dipsogenic genes associated with weight changes during Ironman Triathlons.

Thirst is regulated by a complex interaction of signalling pathways within the central nervous system, including components of the renin-angiotensin and kalikrein kinin systems, as well as the serotonergic pathways. The aim of this study was to determine whether there were any associations between polymorphisms within the ACE, BDKRB2, NOS3 and/or 5-HTT genes with weight changes during the 2000 and 2001 226 km South African Ironman Triathlons. Pre- and post-race serum [Na(+)] and body weights, as well as genotype data, were collected from 428 (61.1%) Caucasian male triathletes who were divided into three groups according to their relative weight loss during the triathlon (0-3, 3-5 and >5%). There was a significant linear trend for the distribution of both the BDKRB2 +9/+9 genotype and the 5-HTT SS genotype between the three weight loss groups, with the >5% group having the highest percentage of athletes with the +9/+9 genotype (chi(2)=5.3, P=0.021) and the highest percentage of athletes with the SS genotype (chi(2)=5.8, P=0.016). Likewise, the >5% group had the highest percentage of athletes with the combined SS 5-HTT and/or +9/+9 BDKRB2 genotypes (chi(2)=7.4, P=0.007). In conclusion, the functional SS genotype of the serotonin transporter-linked polymorphic region (5-HTTLPR) within the 5-HTT gene and the functional +9/+9 genotype of the BDKBR2 gene were associated with larger weight losses during the Ironman Triathlons. These findings suggest the involvement of the serotonergic pathways in the control of thirst and drinking behaviour and provide further evidence for the dipsogenic effect of circulating bradykinin.

The bradykinin beta 2 receptor (BDKRB2) and endothelial nitric oxide synthase 3 (NOS3) genes and endurance performance during Ironman Triathlons.

We have previously shown that the insertion allele of the angiotensin-converting enzyme (ACE) gene was over-represented in the fastest South-African-born finishers of the South African Ironman Triathlons. As ACE is a component of the skeletal muscle kallikrein-kinin system (KKS), the aim of this study is to determine if there are any further associations between polymorphisms within the BDKRB2 and NOS3 genes, which encode for the KKS components, bradykinin beta(2) receptor and nitric oxide synthase, respectively, and ultra-endurance performance during the Ironman Triathlons. Four-hundred and forty-three male Caucasian triathletes who completed the 2000 and/or 2001 South African Ironman Triathlons and 203 healthy Caucasian male control subjects were genotyped for the functional -9/+9 polymorphism within exon 1 of the BDKRB2 gene and the G894T NOS3 gene polymorphisms. The BDKRB2 -9/-9 genotype occurred at a significantly higher frequency when the triathlete group (27.0%) was compared with the control group (19.3%, P=0.035). When divided into tertiles, there was also a significant linear trend for the NOS3 GG genotype distribution among the fastest (35.0%), middle (40.4%) and slowest (46.9%) finishers (P=0.039). The overall finishing times of the triathletes with an NOS3 GG genotype together with a BDKRB2 +9 allele were significantly slower than those with other genotype combinations (P=0.001). The NOS3/BDKRB2 genotype (beta=-0.150, B=-31.48, P=0.002), together with body mass index and age, accounted for 14.6% of the variance in the overall race time for the triathlon. In conclusion, both the NOS3 and BDKRB2 genes are associated with the actual performance during the Ironman Triathlons.

The ACE gene and endurance performance during the South African Ironman Triathlons.

PURPOSE: Several studies have suggested that the insertion (I) variant rather than the deletion (D) variant of the human angiotensin-converting enzyme (ACE) gene is associated with elite endurance performance. The aim of this study was to determine whether the ID polymorphism is associated with the performance of the fastest finishers of the South African Ironman Triathlons. METHODS: A total of 447 Caucasian male triathletes of a variety of nationalities and athletic ability who completed either the 2000 or 2001 South African Ironman Triathlons and 199 Caucasian male control subjects were genotyped for the ACE ID polymorphism. RESULTS: There was a significantly higher frequency of the I allele in the fastest 100 South African-born finishers (103 I, 51.5% and 97 D, 48.5%) compared with the 166 South African-born control subjects (140 I, 42.2% and 192 D, 57.8%) (P = 0.036). There was also a significant linear trend for the allele distribution among the fastest 100 finishers (I allele = 51.5%), slowest 100 finishers (I allele = 47.5%), and control (I allele = 42.2%) South African-born subjects (P = 0.033). There was, however, no significant difference in the ACE genotype or allele frequencies when athletes born outside South Africa were analyzed. CONCLUSION: To our knowledge this is the first study that has examined the effect of an athlete's ACE genotype on their actual performance during an ultra-endurance race. The I allele of the ACE gene was associated with the endurance performance of the fastest 100 South African-born finishers in these triathlons.