[Consanguinity and congenital abnormalities].

Knowledge of consanguinity is relevant for employees in the Danish national health service, since about 7.5% of the Danish population has another ethnic background than Danish and the majority comes from cultures where consanguineous marriages are not unusual. In the literature it is found that consanguineous couples have a higher risk of having children with congenital malformations. The risk is increased by a factor 2 to 2 1/2. The average risk in Denmark is about 3%. Primarily, the autosomal recessive diseases are expressed in children with consanguineous parents. In order to advise and diagnose it is essential to clarify the consanguinity state. In case of pregnancy with consanguineous parents, we recommend: 1) Counselling to estimate the risk of foetal illness and information about possible examination possibilities. 2) An ultrasound scan at the gestational age of 11-14 weeks in order to measure nuchal translucency and an early malformation scan. 3) An ultrasound scan for malformations at the gestational age of 18-20 weeks. 4) An ultrasound scan especially in order to detect foetal heart malformations at the gestational age of 20-24 weeks.