Erasmus University Medical Center

About: Erasmus University Medical Center is a healthcare organization based out in Rotterdam, Zuid-Holland, Netherlands. It is known for research contribution in the topics: Population & Medicine. The organization has 8162 authors who have published 11395 publications receiving 517117 citations.

Three Genome-wide Association Studies and a Linkage Analysis Identify HERC2 as a Human Iris Color Gene

Abstract: Human iris color was one of the first traits for which Mendelian segregation was established. To date, the genetics of iris color is still not fully understood and is of interest, particularly in view of forensic applications. In three independent genome-wide association (GWA) studies of a total of 1406 persons and a genome-wide linkage study of 1292 relatives, all from the Netherlands, we found that the 15q13.1 region is the predominant region involved in human iris color. There were no other regions showing consistent genome-wide evidence for association and linkage to iris color. Single nucleotide polymorphisms (SNPs) in the HERC2 gene and, to a lesser extent, in the neighboring OCA2 gene were independently associated to iris color variation. OCA2 has been implicated in iris color previously. A replication study within two populations confirmed that the HERC2 gene is a new and significant determinant of human iris color variation, in addition to OCA2. Furthermore, HERC2 rs916977 showed a clinal allele distribution across 23 European populations, which was significantly correlated to iris color variation. We suggest that genetic variants regulating expression of the OCA2 gene exist in the HERC2 gene or, alternatively, within the 11.7 kb of sequence between OCA2 and HERC2, and that most iris color variation in Europeans is explained by those two genes. Testing markers in the HERC2-OCA2 region may be useful in forensic applications to predict eye color phenotypes of unknown persons of European genetic origin.

Best Practices and Joint Calling of the HumanExome BeadChip: The CHARGE Consortium

Abstract: Genotyping arrays are a cost effective approach when typing previously-identified genetic polymorphisms in large numbers of samples. One limitation of genotyping arrays with rare variants (e.g., minor allele frequency [MAF] <0.01) is the difficulty that automated clustering algorithms have to accurately detect and assign genotype calls. Combining intensity data from large numbers of samples may increase the ability to accurately call the genotypes of rare variants. Approximately 62,000 ethnically diverse samples from eleven Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium cohorts were genotyped with the Illumina HumanExome BeadChip across seven genotyping centers. The raw data files for the samples were assembled into a single project for joint calling. To assess the quality of the joint calling, concordance of genotypes in a subset of individuals having both exome chip and exome sequence data was analyzed. After exclusion of low performing SNPs on the exome chip and non-overlap of SNPs derived from sequence data, genotypes of 185,119 variants (11,356 were monomorphic) were compared in 530 individuals that had whole exome sequence data. A total of 98,113,070 pairs of genotypes were tested and 99.77% were concordant, 0.14% had missing data, and 0.09% were discordant. We report that joint calling allows the ability to accurately genotype rare variation using array technology when large sample sizes are available and best practices are followed. The cluster file from this experiment is available at www.chargeconsortium.com/main/exomechip.

Perceived parenting style and practices and the consumption of sugar-sweetened beverages by adolescents

Abstract: The purpose of this study was to investigate whether perceived parenting practices and parenting style dimensions (strictness and involvement) are associated with adolescents' consumption of sugar-sweetened beverages. In this cross-sectional study, secondary school students (n = 383, mean age 13.5 years) completed a self-administered questionnaire on their consumption of sugar-sweetened beverages, attitude, social influences, self-efficacy, habit strength, food-related parenting practices and the general parenting style dimensions of 'strictness' and 'involvement'. Data were analyzed using multiple linear regression analyses. More restrictive parenting practices were associated with lower consumption of sugar-sweetened beverages (β = -38.0 ml; 95% CI = -48.1, -28.0). This association was highly mediated (∼55%) by attitude, self-efficacy and modeling from parents. Nevertheless, a significant direct effect remained (β = -17.1 ml; 95% CI = -27.2, -6.90). Interactions between perceived parenting style and parenting practices showed that the association between parenting practices and sugar-sweetened beverage consumption was stronger among adolescents who perceived their parents as being moderately strict and highly involved. Parents influence their children's sugar-sweetened beverage consumption and should therefore be involved in interventions aimed at changing dietary behaviors. Interventions aimed at the promotion of healthy parenting practices will improve when they are tailored to the general parenting style of the participants.