Dorret I. Boomsma1
The Netherlands Twin Register (NTR) was established in 1987 and is used as a research tool for developmental genetic studies in newborn twins and for longitudinal genetic studies in adolescent and young-adult twins and their families. The NTR registers around 50% of all newborn twins in The Netherlands each year. In 1987, 936 twin pairs and in 1995 1527 twin pairs were registered. All parents of young twins receive questionnaires about growth and development every one to two years. In the entire sample of newborn twins data on birth weight, height and growth, motor development, health- and behavior problems are collected. At ages 3, 7, 10 and 12 years childhood psychopathology is assessed by the Child Behavior Check List (CBCL). Results in 4000 3-year old twin pairs show high heritabilities for nearly all dimensions of behavioral problems. Subsamples of twins participate in specific projects. Over 200 twin pairs participated in a study of brain maturation (at ages 5 and 7 years), and cognition (at ages 5, 7, 10 and 12 years). This sample is also used to study the association of cognition with childhood behavioral problems. We have good experiences with collecting DNA samples via mouth swabs. Currently, these samples are used to determine zygosity.
Address: De Boelelaan 1111, 1081 HV Amsterdam, The Netherlands, Phone 31-20-4448787, Fax 31-20-4448832, Email: dorret@psy.vu.nl
1Vrije Universiteit, Dept of Biological Psychology