ABSTRACT
Objective To analyze the variations of PTPS gene in patients with suspected 6-pyruvoyl-tetra hydropterin synthase deficiency (PTPSD) and to make prenatal diagnosis in high-risk families. Methods Chemiluminescence was used for phenylalanine detection in blood or dried blood spots.Patients with phenylalanine concentration over 120μmol/L were detected by urine pterin analysis, and the activity of dihydropteridine reductase (DHPR) was detected. tetrahydrobiopterin loading tests were performed in suspected patients with abnormal urinary pterin profiles. PTPS gene variation analysis was performed by direct Sanger sequencing based on PCR amplification. Prenatal diagnosis in 7 high-risk families was performed by chorionic villus sampling when the genotype was identified. Results In 656 patients with hyperphenylalanine, 22 cases were diagnosed as PTPSD clinically. 16 variations were detected in the 22 PTPSD cases. The 5 variations, p.Lys77Arg, p.Ile84Phe, c.315-2A>G, c.244-2A>T, c.187-1G>T, were identified as novel variations. Two fetuses carried the same mutation with the proband and therefore were thought to be PTPSD fetuses. Three fetuses carried only one mutant allele and thus were thought to be PTPSD carriers.