It took the combined skills of 21 researchers to tease out four new risk factors for type 2 diabetes mellitus.

A team led by Phillipe Froguel at the Pasteur Institute in Paris, France, provided the samples, phenotypes and assistance with data analysis, while researchers at McGill University in Montreal, Canada, handled the genotyping and data analysis.

Essential to that task was Rob Sladek, who has both an MD and an engineering degree. “He's very good with machines and with calculations,” says co-author Constantin Polychronakos at McGill. “He was instrumental in setting up the technology and the bioinformatics.” High-density bead-based microarrays enabled the team to analyse 400,000 single-nucleotide polymorphisms from 1,300 individuals.

Polychronakos decided to exclude people with the known risk factor of obesity from the study. “I wanted to see what else is there that makes people diabetic.” The all-important statistical advice was provided by David Balding, at Imperial College, London, UK.

Four genes were identified as new risk factors for type 2 diabetes and a known association was confirmed (see page 881). Further study of these genes may help explain how the disease works.