A NEWBORN WITH CONGENITAL ABNORMALITIES

This infant has multiple congenital abnormalities. The explanation given to the parents by the junior doctor must be honest but gentle, and should avoid speculation about prognosis. It would be appropriate to explain that congenital abnormalities are quite common, but in addition to the ear abnormalities the parents have noticed, there are other abnormalities, which need to be assessed by a more senior colleague. The iris coloboma and the genital abnormalities can be pointed out and the heart murmur should be mentioned. The combination of multiple abnormalities suggests an underlying cause or syndrome. The parents will be upset by the news, but will appreciate honesty and hard work in order to give them further information as soon as possible. Congenital anomalies affect about 3 per cent of live births, although not all of these are obvious at the time of birth. They can be divided into malformations due to errors during morphogenesis, and deformations which affect a previously normally formed part of the fetus. Most malformations do not have a defined aetiology and are considered sporadic.

Causes of congenital malformations

• Genetic – chromosomal abnormalities, e.g. 22q11 deletion (DiGeorge syndrome) – gene defects, e.g. CHD7 (chromodomain helicase DNA-binding protein 7 mutations causing CHARGE syndrome)

• Environmental – maternal factors, e.g. diabetes (cardiac malformations) – prescribed drugs, e.g. phenytoin (fetal hydantoin syndrome) – recreational drugs, e.g. alcohol (fetal alcohol syndrome) – environmental toxins, e.g. dioxins (central nervous system anomalies) – infections (e.g. rubella, cytomegalovirus)

• Sporadic

Assessment of a child with multiple congenital abnormalities should determine whether there are other abnormalities, the severity of those already detected, and the underlying cause if possible. Sometimes a characteristic pattern of abnormalities will reveal the diagnosis. Karyotyping should be performed and other specific genetic tests may be required. A clinical geneticist should be asked to assess the child if a unifying diagnosis is not apparent. In this case the findings suggest CHARGE syndrome (coloboma, heart defects, atresia choanae, retardation of growth and development, genital and ear abnormalities). Although there is no respiratory distress, choanal atresia should be excluded (by attempting to pass a nasogastric tube through each nostril). The cardiovascular examination findings would be consistent with a ventricular septal defect, the commonest congenital heart defect. Further assessments by a paediatric cardiologist, ophthalmologist, endocrinologist, urologist, audiological physician and developmental paediatrician will be needed. Making a diagnosis may allow future problems to be anticipated and allows genetic counselling about the recurrence risk in future pregnancies.

KEY POINTS

• Congenital abnormalities are common.

• If one congenital abnormality is present, you should look for other ones.

• Recognizing a pattern of abnormalities comprising a syndrome is important for prognosis and genetic counselling