Mutation analysis of patients with 6-pyruvoyltetrahydropterin synthase deficiency in Henan / 中华实用儿科临床杂志

ABSTRACT

Objective:To analyze the variation and characteristics of gene mutation in patients with 6-pyruvoyltetrahydropterin synthase deficiency(PTPSD) in Henan province, and to provide the theoretical basis for early diagnosis, treatment, genetic consultation and prenatal diagnosis of PTPSD.Methods:One thousand nine hundred and six children with hyperphenylalaninemia (HPA) treated in Henan Neonatal Screening Center, the Third Affiliated Hospital of Zhengzhou University from January 1998 to December 2018 were included.Chemiluminescence was used for pheny-lalanine (Phe) detection in blood or dried blood spots.For patients with Phe concentration >120 μmol/L, urine pterin analysis was carried out, and the activity of dihydropteridine reductase (DHPR) was detected.Mutations of the PAH, GCH1, GFRP, PCBD1, PTPS and QDPR in 79 children with tetrahydrobiopterin deficiency(BH4D) were detected by using the high-throughput sequencing.All variations were verified by Sanger sequencing. Results:Among the 1 906 children, 79 cases were diagnosed as BH4D clinically, and they all were PTPSD.The incidence of PTPSD in HPA in Henan was 4.14%.One hundred and fifty-six out of 158 alleles in 79 children were detected, and the detection rate of gene mutation was 98.73%, 30 mutations were identified and most of the variants were located in exons 5(92/156 cases, 58.97%). Variants of c. 259C>T (61/156 cases, 39.10%), c.286G>A (17/156 cases, 10.90%), c.155A>G (13/156 cases, 8.33%) and c. 272A > G (10/156 cases, 6.41%) were more common.Six novel variations were detected, which included c. -77G>T, c.158A>G, c.262C>T, c.207G>A, c.316A>G and c. 332C>G; 38 genotypes had been identified, including 3 homozygous mutations and 33 compound heterozygous mutations.Conclusions:c. 259C>T is the hot-spots gene mutation in Chinese PTPSD patients in Henan province.The identification of 6 new mutations enriches the gene mutation profile.