The Guangzhou Twin Project: an update.

The Guangzhou Twin Registry is a population-based registry of twins residing in Guangzhou City. The initial registry database included 9,700 pairs of young twins recruited from the Official Household Registry of Guangzhou City. The registry is designed to provide a resource to identify the genetic and environmental causes of common diseases with an initial focus on eye diseases. From 2006 onward, phenotype and DNA collection have been completed for more than 1,200 twin pairs and their parents or siblings. Most of the young twins have come back for an annual examination of the progressive traits, such as refraction, ocular biometry, weight, and height. Genome-wide association scans have been completed recently. This article gives an update of the study design, cohort profile, previous findings, and future directions. Results from the Guangzhou Twin Project may contribute to the understanding of gene-environmental interplay for complex diseases in both adults and children.