Within this line of research, the 'Obstetrics and Prenatal Diagnostics' research group carries out studies into the distinction between heredity and environment in twins.

Fund TWINS (Dutch website) encourage scientific research with multiples and support the East Flanders Prospective Twin Survey (EFPTS). Since 1964, the EFPTS registers multiples born in East-Flanders. Every maternity in East Flanders participate and more than 98% of the multiple births are registered. The EFPTS is unique in the world and contains a wealth of information of more than 10 000 multiples for researchers.

Data and sample collection

EFPTS has several unique features: it is population-based and prospective, with the possibility of long-term follow-up.

Importance of studies with multiple births

The DNA of monozygotic twins is identical. Dizygotic twins are, just like brother and sister, genetically equal for 50%. By comparing information of monozygotic and dizygotic twins, researchers gain insight into the role of nature vs nurture.

If the genetic factors (nature) have a low impact, the environmental factors (nurture) can be determined.

Monozygotic twins

Monozygotic twins originate from the fertilisation of 1 oocyte by 1 sperm, after fertilisation, the oocyte split into 2 identical parts. We can define 3 groups of monozygotic twins: monochorial monoamniotic, monochorial diamniotic, dichorial diamniotic, depending on the time of splitting of the oocyte. Monozygotic twins are genetically identical and have always the same sex. 

Dizygotic twins

Dizygotic twins originate from two oocytes that each are fertilized by 1 sperm. The twins are 50% genetically identical, like brother and sister. Dizygotic twins can have the same or opposite sex. 

Ongoing research projects

A study of the placental methylome of dichorionic and monochorionic monozygotic twin pairs to establish a timeline of epigenetic programming

The health and disease hypothesis's developmental origin states that antenatal and early life exposure to a suboptimal environment can predispose to adverse health outcomes in adult life, such as cardiometabolic disease. Modification of the epigenome, and more specifically the methylome, seems a plausible mechanism for this. Although monozygotic twins are genetically identical, they can differ phenotypically, for example in birth weight. Phenotype and methylome differences attributable to genetic and maternal differences can be ruled out, meaning that intra-pair differences must be a result of variation in their prenatal environment. Furthermore, the moment of splitting defines the point from which twins can experience environmental differences.

The objective is to investigate the effect of the moment of splitting (chorionicity) on the placental and saliva (in adulthood) methylome and cardiometabolic disease risk in monozygotic twin pairs. Birth weight discordance will be used as an indicator of prenatal environmental heterogeneity between the twins.

  • researchers: Dr. Marij Gielen (Maastricht University) and prof. dr. Steven Weyers (Ghent University)

The influence of the environment on black carbon in placental tissue

For years the East Flanders Prospective Twin Survey and the Centre for Environmental Sciences are collaborating. Studies show that good air quality is beneficial for the unborn child and may also affect health later in life. We want to investigate the residential environment during pregnancy, especially traffic exposure at the residence, in association with the internal black carbon load in placental tissue and the underlying mechanisms involved.

CollaborationCollaboration fund TWINS

Fund TWINS is a collaboration between different universities namely the University of Ghent, Leuven Hasselt and Maastricht. Fund TWINS is located at the Gent University hospital.

Request for collaboration

The study has an open policy in regard to collaboration with other research groups. Requests for collaboration should primarily be pointed to the chairmen of Fund TWINS Prof. dr. Steven Weyers. These requests are discussed in the scientific board regarding their study aims, overlap with ongoing studies, logistic consequences and financial contributions. After approval of the project by the scientific board, the project can be submitted to the ethical committee of UZ Gent for ethical approval.



The TWINS study team is responsible for the organization and follow-up of the TWINS Fund.

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