Development of an instrument for the evaluation of advanced life support performance.

BACKGROUND: Assessing advanced life support (ALS) competence requires validated instruments. Existing instruments include aspects of technical skills (TS), non-technical skills (NTS) or both, but one instrument for detailed assessment that suits all resuscitation situations is lacking. This study aimed to develop an instrument for the evaluation of the overall ALS performance of the whole team. METHODS: This instrument development study had four phases. First, we reviewed literature and resuscitation guidelines to explore items to include in the instrument. Thereafter, we interviewed resuscitation team professionals (n = 66), using the critical incident technique, to determine possible additional aspects associated with the performance of ALS. Second, we developed an instrument based on the findings. Third, we used an expert panel (n = 20) to assess the validity of the developed instrument. Finally, we revised the instrument based on the experts' comments and tested it with six experts who evaluated 22 video recorded resuscitations. RESULTS: The final version of the developed instrument had 69 items divided into adherence to guidelines (28 items), clinical decision-making (5 items), workload management (12 items), team behaviour (8 items), information management (6 items), patient integrity and consideration of laymen (4 items) and work routines (6 items). The Cronbach's α values were good, and strong correlations between the overall performance and the instrument were observed. CONCLUSION: The instrument may be useful for detailed assessment of the team's overall performance, but the numerous items make the use demanding. The instrument is still under development, and more research is needed to determine its psychometric properties.

Neuronal ceroid lipofuscinosis genes, CLN2, CLN3 and CLN5 are spatially and temporally co-expressed in a developing mouse brain.

Neuronal ceroid lipofuscinosis (NCL) diseases consist of a group of genetically inherited neurodegenerative disorders that share common symptoms such as seizures, psychomotor retardation, blindness, and premature death. Although gene defects behind the NCL diseases are well characterized, very little is known how these defects affect normal development of the brain and cause the pathology of the disease. To obtain understanding of the development of the cell types that are mostly affected by defective function of CLN proteins, timing of expression of CLN2, CLN3 and CLN5 genes was investigated in developing mouse brain. The relationship between the expression pattern and the developmental stage of the brain showed that these genes are co-expressed spatially and temporally during brain development. Throughout the development strong expression of the three mRNAs was detected in germinal epithelium and in ventricle regions, hippocampus and cerebellum, all representing regions that are known to be associated with the formation of new neurons. More specifically, RT-PCR studies on developing mouse cortices revealed that the CLN genes were temporally co-expressed in the neural progenitor cells together with known stem cell markers. This suggested that CLN2, CLN3 and CLN5 genes may play an important role in early embryonal neurogenesis.

Is it advantageous to use quality by design (QbD) to develop nanoparticle-based dosage forms for parenteral drug administration?

Parenteral administration is one of the most commonly used drug delivery routes for nanoparticle-based dosage forms, such as lipid-based and polymeric nanoparticles. For the treatment of various diseases, parenteral administration include intravenous, subcutaneous, and intramuscular route. In drug development phase, multiparameter strategy with a focus on drug physicochemical properties and the specificity of the administration route is required. Nanoparticle properties in terms of size and targeted delivery, among others, are able to surpass many drawbacks of conventional dosage forms, but these unique properties can be a bottleneck for approval by regulatory authorities. Quality by Design (QbD) approach has been widely utilized in development of parenteral nanoparticle-based dosage forms. It fosters knowledge of product and process quality by involving sound scientific data and risk assessment strategies. A full and comprehensive investigation into the state of implementation and applications of the QbD approach in these complex drug products can highlight the gaps and challenges. In this review, the analysis of critical attributes and Design of Experiment (DoE) approach in different nanoparticulate systems, together with the proper utilization of Process Analytical Technology (PAT) applications are described. The essential of QbD approach for the design and development of nanoparticle-based dosage forms for delivery via parenteral routes is discussed thoroughly.

Meta-analysis of genome-wide association studies for personality.

Personality can be thought of as a set of characteristics that influence people's thoughts, feelings and behavior across a variety of settings. Variation in personality is predictive of many outcomes in life, including mental health. Here we report on a meta-analysis of genome-wide association (GWA) data for personality in 10 discovery samples (17,375 adults) and five in silico replication samples (3294 adults). All participants were of European ancestry. Personality scores for Neuroticism, Extraversion, Openness to Experience, Agreeableness and Conscientiousness were based on the NEO Five-Factor Inventory. Genotype data of ≈ 2.4M single-nucleotide polymorphisms (SNPs; directly typed and imputed using HapMap data) were available. In the discovery samples, classical association analyses were performed under an additive model followed by meta-analysis using the weighted inverse variance method. Results showed genome-wide significance for Openness to Experience near the RASA1 gene on 5q14.3 (rs1477268 and rs2032794, P=2.8 × 10(-8) and 3.1 × 10(-8)) and for Conscientiousness in the brain-expressed KATNAL2 gene on 18q21.1 (rs2576037, P=4.9 × 10(-8)). We further conducted a gene-based test that confirmed the association of KATNAL2 to Conscientiousness. In silico replication did not, however, show significant associations of the top SNPs with Openness and Conscientiousness, although the direction of effect of the KATNAL2 SNP on Conscientiousness was consistent in all replication samples. Larger scale GWA studies and alternative approaches are required for confirmation of KATNAL2 as a novel gene affecting Conscientiousness.

The locus for Meckel syndrome with multiple congenital anomalies maps to chromosome 17q21-q24.

Autosomal recessive Meckel syndrome (OMIM 249000) (MES), first described in 1822 by Johann F. Meckel, is a major monogenic malformation syndrome with a neural tube defect leading to death of the fetus in utero or shortly after birth. The hallmarks of the syndrome are occipital meningoencephalocele, very large kidneys with multicystic dysplasia, cystic and fibrotic changes of the liver and polydactyly (Fig. 1). Other typical malformations for MES are cleft lip and palate, urinary tract anomalies, ambiguous genitals in the males and club feet. Although MES has been reported worldwide, reports on the true birth prevalence of MES in different populations are scarce. In Finland MES is effectively screened and relatively frequent with a birth prevalence of 1:9,000 and a disease gene frequency of 0.01 (ref.4) which is of the same order of magnitude as that of the most common recessive diseases belonging to the 'Finnish disease heritage', that is genetic disorders enriched or only encountered in Finland. However, in MES, comparable or even higher incidences are also reported from other populations. Here, we report the assignment of the MES locus to chromosome 17q21-q24 in the 13 cM region, and exclude some of the potential candidate genes located in this critical chromosomal region.

An autosomal locus causing autoimmune disease: autoimmune polyglandular disease type I assigned to chromosome 21.

Autoimmune polyglandular disease type I (APECED) is an autosomal recessive autoimmune disease characterized by a variable combination of the failure of the endocrine glands. The pathogenesis of this unique autoimmune disease is unknown; unlike many other autoimmune diseases, APECED does not show association to specific HLA haplotypes. Unravelling the APECED locus will identify a novel gene outside the HLA loci influencing the outcome of autoimmune diseases. We have assigned the disease locus to chromosome 21q22.3 by linkage analyses in 14 Finnish families. Linkage disequilibrium studies have significantly increased the informativeness of the analyses and helped to locate the critical DNA region for the APECED locus to just 500 kilobases, a much more precise definition than linkage analyses alone could achieve.

Mutations in the fibrillin gene responsible for dominant ectopia lentis and neonatal Marfan syndrome.

Mutations in the gene coding for fibrillin on chromosome 15 (FBN1) are known to cause Marfan syndrome (MFS). A related disorder, dominant ectopia lentis (EL), has also been linked genetically to this locus. We now describe ten novel mutations of FBN1 resulting in strikingly different phenotypes. In addition to classic MFS, FBN1 mutations also give rise to EL and a severe neonatal form of MFS. Interestingly, the neonatal MFS mutations are clustered in one particular region of FBN1, possibly providing new insights into genotype-phenotype comparisons.

CLN5, a novel gene encoding a putative transmembrane protein mutated in Finnish variant late infantile neuronal ceroid lipofuscinosis.

The neuronal ceroid lipofuscinoses (NCLs) represent a group of common recessive inherited neurodegenerative disorders of childhood, with an incidence of 1:12,500 live births. They are characterized by accumulation of autofluorescent lipopigments in various tissues. Several forms of NCLs have been identified, based on age at onset, progression of disease, neurophysiological and histopathological findings and separate genetic loci. All types of NCL cause progressive visual and mental decline, motor disturbance, epilepsy and behavioral changes, and lead to premature death. One of the subtypes, Finnish variant late infantile neuronal ceroid lipofuscinosis (vLINCL; MIM256731) affects children at 4-7 years of age. The first symptom is motor clumsiness, followed by progressive visual failure, mental and motor deterioration and later by myoclonia and seizures. We have previously reported linkage for vLINCL on chromosome 13 (ref. 5) and constructed a long-range physical map over the region. Here, we report the positional cloning of a novel gene, CLN5, underlying this severe neurological disorder. The gene encodes a putative transmembrane protein which shows no homology to previously reported proteins. Sequence analysis of DNA samples from patients with three different haplotypes revealed three mutations; one deletion, one nonsense and one missense mutation, suggesting that mutations in this gene are responsible for vLINCL.

An autosomal locus predisposing to deletions of mitochondrial DNA.

The molecular mechanisms by which the nuclear genome regulates the biosynthesis of mitochondrial DNA (mtDNA) are only beginning to be unravelled. A naturally occurring in vivo model for a defect in this cross-talk of two physically separate genomes is a human disease, an autosomal dominant progressive external ophthalmoplegia, in which multiple deletions of mtDNA accumulate in the patients' tissues. The assignment of this disease locus to 10q 23.3-24.3 is the first direct evidence for involvement of both nuclear and mitochondrial genomes in a single disorder.

A putative vulnerability locus to multiple sclerosis maps to 5p14-p12 in a region syntenic to the murine locus Eae2.

Multiple sclerosis (MS) is a chronic inflammatory disorder characterized by multifocal damage of myelin in the central nervous system (CNS). The prevalence of this putative autoimmune disease is 0.1% in individuals of northern European origin. Family, adoption and twin studies implicate genetic factors in the aetiology. MS is widely speculated to be a multifactorial disorder with a complex mode of inheritance. Despite many studies of candidate genes, only an association with HLA-DR2-DQ6 has been generally detected, and the number of susceptibility genes remains unknown. The chronic variant of experimental allergic encephalomyelitis (EAE), a T-cell mediated autoimmune disease in rodents, represents a relevant animal model for MS given the chronic relapsing disease course and inflammatory changes of CNS observed in these demyelinating disorders. Susceptibility to EAE is also influenced by the major histocompatibility complex (MHC). Human syntenic regions to murine loci predisposing to EAE were tested as candidate regions for genetic susceptibility of MS. Three chromosomal regions (1p22-q23, 5p14-p12 and Xq13.2-q22) were screened in 21 Finnish multiplex MS families most originating from a high risk region in western Finland. Several markers yielded positive lod scores on 5p14-p12, syntenic to the murine locus Eae2. Our data provide evidence for a predisposing locus for MS on 5p14-p12.

Loss-of-function mutations in TYROBP (DAP12) result in a presenile dementia with bone cysts.

Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL; MIM 221770), also known as Nasu-Hakola disease, is a recessively inherited disease characterized by a combination of psychotic symptoms rapidly progressing to presenile dementia and bone cysts restricted to wrists and ankles. PLOSL has a global distribution, although most of the patients have been diagnosed in Finland and Japan, with an estimated population prevalence of 2x10-6 (ref. 2) in the Finns. We have previously identified a shared 153-kb ancestor haplotype in all Finnish disease alleles between markers D19S1175 and D19S608 on chromosome 19q13.1 (refs 5,6). Here we characterize the molecular defect in PLOSL by identifying one large deletion in all Finnish PLOSL alleles and another mutation in a Japanese patient, both representing loss-of-function mutations, in the gene encoding TYRO protein tyrosine kinase binding protein (TYROBP; formerly DAP12). TYROBP is a transmembrane protein that has been recognized as a key activating signal transduction element in natural killer (NK) cells. On the plasma membrane of NK cells, TYROBP associates with activating receptors recognizing major histocompatibility complex (MHC) class I molecules. No abnormalities in NK cell function were detected in PLOSL patients homozygous for a null allele of TYROBP.

Linkage of familial combined hyperlipidaemia to chromosome 1q21-q23.

More than half of the patients with angiographically confirmed premature coronary heart disease (CHD) have a familial lipoprotein disorder. Familial combined hyperlipidaemia (FCHL) represents the most common genetic dyslipidemia with a prevalence of 1.0-2.0%. FCHL is estimated to cause 10-20% of premature CHD and is characterized by elevated levels of cholesterol, triglycerides, or both. Attempts to characterize genes predisposing to FCHL have been hampered by its equivocal phenotype definition, unknown mode of inheritance and genetic heterogeneity. In order to minimize genetic heterogeneity, we chose 31 extended FCHL families from the isolated Finnish population that fulfilled strictly defined criteria for the phenotype status. We performed linkage analyses with markers from ten chromosomal regions that contain lipid-metabolism candidate genes. One marker, D1S104, adjacent to the apolipoprotein A-II (APOA2) gene on chromosome 1, revealed a lod score of Z = 3.50 assuming a dominant mode of inheritance. Multipoint analysis combining information from D1S104 and the neighbouring marker D1S1677 resulted in a lod score of 5.93. Physical positioning of known genes in the area (APOA2 and three selectin genes) outside the linked region suggests a novel locus for FCHL on 1q21-q23. A second paper in this issue (Castellani et al.) reports the identification of a mouse combined hyperlipidaemia locus in the syntenic region of the mouse genome, thus further implicating a gene in this region in the aetiology of FCHL.

A new gene, encoding an anion transporter, is mutated in sialic acid storage diseases.

Sialic acid storage diseases (SASD, MIM 269920) are autosomal recessive neurodegenerative disorders that may present as a severe infantile form (ISSD) or a slowly progressive adult form, which is prevalent in Finland (Salla disease). The main symptoms are hypotonia, cerebellar ataxia and mental retardation; visceromegaly and coarse features are also present in infantile cases. Progressive cerebellar atrophy and dysmyelination have been documented by magnetic resonance imaging (ref. 4). Enlarged lysosomes are seen on electron microscopic studies and patients excrete large amounts of free sialic acid in urine. A H+/anionic sugar symporter mechanism for sialic acid and glucuronic acid is impaired in lysosomal membranes from Salla and ISSD patients. The locus for Salla disease was assigned to a region of approximately 200 kb on chromosome 6q14-q15 in a linkage study using Finnish families. Salla disease and ISSD were further shown to be allelic disorders. A physical map with P1 and PAC clones was constructed to cover the 200-kb area flanked by the loci D6S280 and D6S1622, providing the basis for precise physical positioning of the gene. Here we describe a new gene, SLC17A5 (also known as AST), encoding a protein (sialin) with a predicted transport function that belongs to a family of anion/cation symporters (ACS). We found a homozygous SLC17A5 mutation (R39C) in five Finnish patients with Salla disease and six different SLC17A5 mutations in six ISSD patients of different ethnic origins. Our observations suggest that mutations in SLC17A5 are the primary cause of lysosomal sialic acid storage diseases.

Association of celiac disease genes with inflammatory bowel disease in Finnish and Swedish patients.

Some genetic loci may affect susceptibility to multiple immune system-related diseases. In the current study, we investigated whether the known susceptibility loci for celiac disease (CelD) also associate with Crohn's disease (CD) and/or ulcerative colitis (UC), the two main forms of inflammatory bowel disease (IBD), in Finnish patients. A total of 45 genetic markers were genotyped in a Finnish data set comprising 699 IBD patients and 2482 controls. Single-marker association with IBD and its subphenotypes was tested. A meta-analysis with a Swedish UC data set was also performed. A total of 12 single-nucleotide polymorphisms associated with CD and/or UC (P<0.05). In the subphenotype analysis, rs6974491-ELMO1 (P=0.0002, odds ratio (OR): 2.20) and rs2298428-UBE2L3 (P=5.44 × 10(-5), OR: 2.59) associated with pediatric UC and CD, respectively. In the meta-analysis, rs4819388-ICOSLG (P=0.00042, OR: 0.79) associated with UC. In the subphenotype meta-analysis, rs1738074-TAGAP (P=7.40 × 10(-5), OR: 0.61), rs6974491-ELMO1 (P=0.00052, OR: 1.73) and rs4819388-ICOSLG (P=0.00019, OR: 0.75) associated with familial UC, pediatric UC and sporadic UC, respectively. Multiple CelD risk loci also confer susceptibility for CD and/or UC in the Finnish and Swedish populations. Certain genetic risk variants may furthermore predispose an individual for developing a particular disease phenotype.

Copy number variations of chromosome 16p13.1 region associated with schizophrenia.

Deletions and reciprocal duplications of the chromosome 16p13.1 region have recently been reported in several cases of autism and mental retardation (MR). As genomic copy number variants found in these two disorders may also associate with schizophrenia, we examined 4345 schizophrenia patients and 35,079 controls from 8 European populations for duplications and deletions at the 16p13.1 locus, using microarray data. We found a threefold excess of duplications and deletions in schizophrenia cases compared with controls, with duplications present in 0.30% of cases versus 0.09% of controls (P=0.007) and deletions in 0.12 % of cases and 0.04% of controls (P>0.05). The region can be divided into three intervals defined by flanking low copy repeats. Duplications spanning intervals I and II showed the most significant (P = 0.00010) association with schizophrenia. The age of onset in duplication and deletion carriers among cases ranged from 12 to 35 years, and the majority were males with a family history of psychiatric disorders. In a single Icelandic family, a duplication spanning intervals I and II was present in two cases of schizophrenia, and individual cases of alcoholism, attention deficit hyperactivity disorder and dyslexia. Candidate genes in the region include NTAN1 and NDE1. We conclude that duplications and perhaps also deletions of chromosome 16p13.1, previously reported to be associated with autism and MR, also confer risk of schizophrenia.

DISC1 association, heterogeneity and interplay in schizophrenia and bipolar disorder.

Disrupted in schizophrenia 1 (DISC1) has been associated with risk of schizophrenia, schizoaffective disorder, bipolar disorder, major depression, autism and Asperger syndrome, but apart from in the original translocation family, true causal variants have yet to be confirmed. Here we report a harmonized association study for DISC1 in European cohorts of schizophrenia and bipolar disorder. We identify regions of significant association, demonstrate allele frequency heterogeneity and provide preliminary evidence for modifying interplay between variants. Whereas no associations survived permutation analysis in the combined data set, significant corrected associations were observed for bipolar disorder at rs1538979 in the Finnish cohorts (uncorrected P=0.00020; corrected P=0.016; odds ratio=2.73+/-95% confidence interval (CI) 1.42-5.27) and at rs821577 in the London cohort (uncorrected P=0.00070; corrected P=0.040; odds ratio=1.64+/-95% CI 1.23-2.19). The rs821577 single nucleotide polymorphism (SNP) showed evidence for increased risk within the combined European cohorts (odds ratio=1.27+/-95% CI 1.07-1.51), even though significant corrected association was not detected (uncorrected P=0.0058; corrected P=0.28). After conditioning the European data set on the two risk alleles, reanalysis revealed a third significant SNP association (uncorrected P=0.00050; corrected P=0.025). This SNP showed evidence for interplay, either increasing or decreasing risk, dependent upon the presence or absence of rs1538979 or rs821577. These findings provide further support for the role of DISC1 in psychiatric illness and demonstrate the presence of locus heterogeneity, with the effect that clinically relevant genetic variants may go undetected by standard analysis of combined cohorts.

Meta-analysis of 32 genome-wide linkage studies of schizophrenia.

A genome scan meta-analysis (GSMA) was carried out on 32 independent genome-wide linkage scan analyses that included 3255 pedigrees with 7413 genotyped cases affected with schizophrenia (SCZ) or related disorders. The primary GSMA divided the autosomes into 120 bins, rank-ordered the bins within each study according to the most positive linkage result in each bin, summed these ranks (weighted for study size) for each bin across studies and determined the empirical probability of a given summed rank (P(SR)) by simulation. Suggestive evidence for linkage was observed in two single bins, on chromosomes 5q (142-168 Mb) and 2q (103-134 Mb). Genome-wide evidence for linkage was detected on chromosome 2q (119-152 Mb) when bin boundaries were shifted to the middle of the previous bins. The primary analysis met empirical criteria for 'aggregate' genome-wide significance, indicating that some or all of 10 bins are likely to contain loci linked to SCZ, including regions of chromosomes 1, 2q, 3q, 4q, 5q, 8p and 10q. In a secondary analysis of 22 studies of European-ancestry samples, suggestive evidence for linkage was observed on chromosome 8p (16-33 Mb). Although the newer genome-wide association methodology has greater power to detect weak associations to single common DNA sequence variants, linkage analysis can detect diverse genetic effects that segregate in families, including multiple rare variants within one locus or several weakly associated loci in the same region. Therefore, the regions supported by this meta-analysis deserve close attention in future studies.

Replication of restless legs syndrome loci in three European populations.

BACKGROUND: Restless legs syndrome (RLS) is associated with common variants in three intronic and intergenic regions in MEIS1, BTBD9, and MAP2K5/LBXCOR1 on chromosomes 2p, 6p and 15q. METHODS: Our study investigated these variants in 649 RLS patients and 1230 controls from the Czech Republic (290 cases and 450 controls), Austria (269 cases and 611 controls) and Finland (90 cases and 169 controls). Ten single nucleotide polymorphisms (SNPs) within the three genomic regions were selected according to the results of previous genome-wide scans. Samples were genotyped using Sequenom platforms. RESULTS: We replicated associations for all loci in the combined samples set (rs2300478 in MEIS1, p = 1.26 x 10(-5), odds ratio (OR) = 1.47, rs3923809 in BTBD9, p = 4.11 x 10(-5), OR = 1.58 and rs6494696 in MAP2K5/LBXCOR1, p = 0.04764, OR = 1.27). Analysing only familial cases against all controls, all three loci were significantly associated. Using sporadic cases only, we could confirm the association only with BTBD9. CONCLUSION: Our study shows that variants in these three loci confer consistent disease risks in patients of European descent. Among the known loci, BTBD9 seems to be the most consistent in its effect on RLS across populations and is also most independent of familial clustering.

Brief report: validity of Finnish registry-based diagnoses of autism with the ADI-R.

AIMS: The aim of the study was to explore the validity of registry-based diagnoses of autism in Finland using the Autism Diagnostic Interview - Revised (ADI-R). This study was designed for the Finnish Prenatal Study of Autism and Autism Spectrum Disorders (FIPS-A), an ongoing research project where registry-based diagnoses will be used for epidemiological studies. METHODS: In this small pilot study, a clinical sample of 95 subjects diagnosed with childhood autism or pervasive developmental disorder/pervasive developmental disorder - not otherwise specified (PDD/PDD-NOS) or Asperger's syndrome according to the Finnish Hospital Discharge Register (FHDR) was gathered nationwide. A small control group consisting of siblings without any registered diagnoses of those being examined was also included in the study. Diagnoses were further re-evaluated by interviewing parents with the ADI-R. RESULTS: The mean scores of autistic subjects clearly exceeded cut-off limits for autism on all three ADI-R domains and 96% of the subjects with registered diagnosis of childhood autism fulfilled the criteria based on the instrument as well. CONCLUSION: These results suggest that the validity of Finnish registry-based diagnoses of childhood autism can be considered good. Our findings lay important groundwork for further population- based studies of the aetiology of autism.

Common candidate gene variants are associated with QT interval duration in the general population.

OBJECTIVES: QT interval prolongation is associated with increased risk of sudden cardiac death at the population level. As 30-40% of the QT-interval variability is heritable, we tested the association of common LQTS and NOS1AP gene variants with QT interval in a Finnish population-based sample. METHODS: We genotyped 12 common LQTS and NOS1AP genetic variants in Health 2000, an epidemiological sample of 5043 Finnish individuals, using Sequenom MALDI-TOF mass spectrometry. ECG parameters were measured from digital 12-lead ECGs and QT intervals were adjusted for age, gender and heart rate with a nomogram (Nc) method derived from the present study population. RESULTS: The KCNE1 D85N minor allele (frequency 1.4%) was associated with a 10.5 ms (SE 1.6) or 0.57 SD prolongation of the adjusted QT(Nc) interval (P=3.6 x 10(-11)) in gender-pooled analysis. In agreement with previous studies, we replicated the association with QT(Nc) interval with minor alleles of KCNH2 intronic SNP rs3807375 [1.6 ms (SE 0.4) or 0.08 SD, P=4.7 x 10(-5)], KCNH2 K897T [-2.6 ms (SE 0.5) or -0.14 SD, P=2.1 x 10(-7)] and NOSA1P variants including rs2880058 [4.0 ms (SE 0.4) or 0.22 SD, P=3.2 x 10(-24)] under additive models. CONCLUSIONS: We demonstrate that each additional copy of the KCNE1 D85N minor allele is associated with a considerable 10.5 ms prolongation of the age-, gender- and heart rate-adjusted QT interval and could thus modulate repolarization-related arrhythmia susceptibility at the population level. In addition, we robustly confirm the previous findings that three independent KCNH2 and NOSA1P variants are associated with adjusted QT interval.