Clinical application of high resolution melting analysis in mutation detection of phenylulanine hydroxylase gene

Abstract

Objective To detect PAH gene mutations in classical PKU patients by HRM analysis. Methods Mutation scanning of PAH gene were performed in 17 classical PKU patients by HRM analysis ( LightScanner), covering the 13 exons and exon-intron boundaries. The HRM results were further confirmed by DNA sequencing, and the sensitivity and specificity of HRM method in PKU diagnosis were also evaluated. In addition, prenatal diagnosis was performed in two fetuses at risk for classical PKU. Results In the 17 patients, two mutations were identified in 16 patients, three mutations were identified in 1 patient.In this subject, a total of 22 different pathogenic mutations : 194V( c. 280A ＞ G), IVS4nt-1 G ＞ A( c. 442-1G ＞ A), R158Q( c. 4736 ＞ A), Q160X( c. 478C ＞ T), W187X( c. 561G ＞ A), E6nt-96A ＞ G( c. 611A ＞G), G239D( c. 716G ＞ A), R241 C( c. 721C ＞ T), R243Q( c. 728G ＞ A), G247R (c. 739G ＞ C), G247V (c. 740G＞T), R261X(c. 781C ＞T), PR261Q(c. 782G ＞ A), H264R (c. 791A ＞ G), F302fsX39 (c. 904delT), E305K( c. 913G ＞ A), G312V( c. 935G ＞ T), Y356X( c. 1068C ＞ A ), V399V ( c. 1197A ＞T), R408Q(c. 1223G ＞ A), T418P(c. 1252A ＞ C) , A434D(c. 1301C ＞ A), 3 silent mutations Q232Q (c. 696G ＞ A), V245V(c. 735G ＞ A), L385L(c. 1155C ＞ G), and one single nucleotide polymorphism rs2280615 ( c. 402A ＞ C) were identified, of which 194V ( c. 280A ＞ G), Q160X ( c. 478C ＞ T), H264R (c. 791A ＞ G), G312V( c. 935G ＞ T) and E305K ( c. 913G ＞ A) were novel mutations identified in PAH gene. The prenatal diagnosis results of the two fetuses : one was diagnosed as normal, the other was diagnosed as a carrier. In this study, the sensitivity and specificity for mutation detection by HRM were 100％, and the HRM results were consistent with DNA sequencing results. Conclusions HRM analysis is a simple,accurate, rapid, high-throughput and low-cost genetic analysis approach. It could be applied to mutation scanning of classical PKU of PAH gene and rapid prenatal diagnosis in parents with known mutations. Key words: Phenylalanine hydroxylase gene; Phenylketonuria; Mutation; Pedigree; Sequence analysis, DNA