Congenital syndromes with malformations of the heart

A look at cardiac development

The foetal heart develops between the third and seventh weeks of pregnancy. Complex folding and looping of what was initially a horseshoe-shaped tube results in the development of the heart with its four chambersIt is in this phase of development that a number of different influences can lead to abnormalities of, and damage to the heart.

The known causes of congenital heart disease can be divided into two groups. The firstis the external group of circumstances that affect the foetus, known as exogenous factors. These include damage caused by drugs or alcohol, and infections contracted by the mother such as rubella (German measles) or cytomegalovirus .

In most cases, however, there is no certain answer to the question of what caused the heart defect – this is known as the multifactor occurrence. Other unspecified exogenous and genetic factors also cause abnormal development of the heart.This applies particularly to children who demonstrate no symptoms other than a congenital heart defect; 90 per cent of the causes of these defects are unclear.However, other anomalies and malformations are also found in about 20 per cent of all children born with a heart defect. Particularly in these cases the cause is probably a genetic disorder, which is either inherited or has occurred spontaneously and for the first time. A genetic cause can be assumed if a heart defect or syndrome occurs frequently or recurrently in one family. It is important that the condition is accurately diagnosed in order to provide the person involved with genetic counselling.

Certain mutations of the human genome give rise to specific clinical pictures, or ‘syndromes’ this is a group of clinically recognisable features that often occur together and are characteristic of a certain clinical condition. Genetic abnormalities can affect whole chromosomes, the numbers of which can differ from those of healthy persons, or entire subsections of chromosomes, which be differently structured. A single gene can also be affected, in which cases one refers to a monogenetic disorder.

Listed below are a number of selected congenital syndromes that often occur in connection with a heart defect.