Phenylketonuria is a genetic disorder affecting one in ten thousand to fifteen thousand babies. It is caused by a deficiency of the enzyme that converts the amino acid phenylalanine to tyrosine. Harmful breakdown products of phenylalanine can damage the child’s developing brain if the condition is not diagnosed early enough, and this leads to cataracts and mental retardation. A blood test performed after birth detects affected babies. Treatment is based on a diet low in phenylalanine. A special formula babymilk is available and if phenylalanine levels are carefully monitored, some breastfeeding may be possible as well. On reaching school age, the diet can usually be relaxed a little, but when an affected woman becomes pregnant and breastfeeds, she should resume the special diet to protect her baby.

Capped child. Such children can be frustrating to look after if they are constantly being compared with other children their own age. It is best to regard them as individuals in their own right and then their slowness is not so difficult to accept. Mentally disabled children thrive with one-to-one attention. This can be hard on the mother, especially if her child is particularly demanding, and regular temporary substitute care helps her to cope without permanently handing her child over to an institution. Playgroups and nursery classes in special schools provide parents with some free time while giving disabled children extra stimulation and opportunity. Parents’ reactions to a mentally disabled child vary a great deal. Some see him or her as a constant source of sorrow. Others say that looking after their child enriches their lives and their relationship with each other.