QDPR gene mutation and clinical follow-up in Chinese patients with dihydropteridine reductase deficiency

• Published in: World journal of pediatrics : WJP 2014-08, Vol.10 (3), p.219-226
• Main Authors: Lu, De-Yun, Ye, Jun, Han, Lian-Shu, Qiu, Wen-Juan, Zhang, Hui-Wen, Zhou, Jian-De, Bao, Pei-Zhong, Zhang, Ya-Fen, Gu, Xue-Fan
• Format: Article
• Language: English
• Subjects: Critical Care Medicine; Imaging; Intensive; Maternal and Child Health; Medicine; Medicine & Public Health; Original Article; Pediatric Surgery; Pediatrics; Radiology; Surgery
• ISSN: 1708-8569; 1867-0687
• DOI: 10.1007/s12519-014-0496-7

Background This study aimed to investigate the mutation spectrum of the QDPR gene, to determine the effect of mutations on dihydropteridine reductase (DHPR) structure/function, to discuss the potential genotypephenotype correlation, and to evaluate the clinical outcome of Chinese patients after treatment. Methods Nine DHPR-deficient patients were enrolled in this study and seven of them underwent neonatal screening. QDPR gene mutations were analyzed and confirmed by routine methods. The potential pathogenicity of missense variants was analyzed using Clustal X, PolyPhen program and Swiss-PDB Viewer 4.04_OSX software, respectively. The clinical outcomes of the patients were evaluated after long-term treatment. Results In 10 mutations of the 9 patients, 4 were novel mutations (G20V, V86D, G130S and A175R), 4 were reported by us previously, and 2 known mutations were identified. R221X was a hotspot mutation (27.7%) in our patients. Eight missense mutations probably had damage to protein. Six patients in this series were treated with a good control of phenylalanine level. The height and weight of the patients were normal at the age of 4 months to 7.5 years. Four patients, who underwent a neonatal screening and were treated early, showed a normal mental development. In 2 patients diagnosed late, neurological symptoms were significantly improved. Conclusions The mutation spectrum of the QDPR gene is different in the Chinese population. Most mutations are related to severe phenotype. The determination of DHPR activity should be performed in patients with hyperphenylalaninemia. DHPR-deficient patients who were treated below the age of 2 months may have a near normal mental development.