Women with phenylketonuria: successful management of pregnancy and implications.

Dietary management of five pregnancies in two women (sisters) with classical phenylketonuria (PKU) is described. One child died neonatally of congenital heart disease and one pregnancy miscarried. Of the three surviving children the only physically and mentally normal child, followed up to eight years, was born after a carefully planned pregnancy with strict dietary control preconceptually and throughout pregnancy. One pregnancy treated dietetically from six weeks gestation resulted in a child mentally normal at seven years but born with oesophageal atresia. The third surviving child is microcephalic and mentally retarded but dietetic treatment did not commence till 28 weeks gestation. It is concluded that to be effective, dietary control must be instituted preconceptually.

Discovery of an inherited bisatellited metacentric microchromosome in amniotic cell culture.

The identification is reported of an extra bisatellited metacentric microchromosome in amniotic cell culture from the third pregnancy of an identical twin (amniocentesis being performed because of age), and its subsequent finding in the maternal parent as an inherited familial marker. The carriers of the microchromosome are all clinically normal and the parents opted for continuation of pregnancy. Only one other report was found in the literature of a similar microchromosome detected in amniotic fluid culture, but we believe ours to be the first bisatellited microchromosome to be clearly identified from an amniotic cell culture using silver staining.

Progeny, pregnancy and phenylketonuria.

Two sisters were diagnosed as having phenylketonuria at the age of 13 years and eight years and having Wechsler IQs of 48-58 and 71-81 respectively. Neither girl was treated with diet. At the age of 21 years the older girl became pregnant. Her blood phenylalanine level was 23mg/100 ml. A low phenylalanine diet, instituted from the 10th week of gestation, maintained her blood phenylalanine levels below 6mg/100ml for the rest of the pregnancy. A female baby, of birth weight 3216g and normal skull size, was delivered at term. The baby died at 14 days of congenital heart disease. Pregnancy in a phenylketonuric woman carries high risks to the fetus. A generation of treated phenylketonuric girls is approaching reproductive life, and doctors and the girls themselves need to be alerted to these risks and the need for strict dietary control during pregnancy. There are probably unrecognised women in the community with phenylketonuria or with hyperphenylalaninaemia whose babies face similar risks. Identification of these women could be achieved by antenatal Guthrie testing.