Molecular studies and prenatal diagnosis of phenylketonuria in Chinese patients.

Phenylketonuria (PKU) is one of the most common inborn errors of metabolic disorders. Although PKU induced mental retardation can be prevented after neonatal screening by following treatment with low phenylalanine diet, some parents are seeking prenatal diagnosis. We screened for mutations in exon 3 and 7 of the PAH gene using the DGGE and restriction enzyme method, in combination with STR linkage analysis. Prenatal diagnosis was carried out in 8 PKU families. With this strategy, we are able to make prenatal diagnosis in about 65-70% PKU families. All diagnosis was confirmed in the newborn.

Neonatal screening of phenylketonuria and congenital hypothyroidism in China.

Mass screening of newborns for some congenital metabolic diseases is a tremendous achievement in the field of preventive medicine. The pilot study of neonatal screening in China was started in 1981. According to the results of 1.1 million newborn screenings from 8 big cities in the past 6 years, the incidence of phenylketonuria was 1/14,767 and congenital hypothyroidism was 1/5,469. China is a vast country with great economic differences among the different regions, making neonatal screening difficult in some areas. The national neonatal screening coverage rate is only about 2 % at the moment, but in metropolitan centers like Shanghai, the coverage rate reached 95 % in 1997.