Association between genotype and phenotype in children with Phenylalanine hydroxylase deficiency in Lianyungang area
10.3760/cma.j.cn511374-20241125-00620
- VernacularTitle:连云港地区苯丙氨酸羟化酶缺乏症患儿的基因型-表型关联研究
- Author:
Shuang LIU
1
;
Qin ZHENG
;
Dandan CUI
;
Wei WANG
;
Leilei WANG
;
Guanghua LUO
Author Information
1. 苏州大学附属第三医院临床医学研究中心，常州 213003
- Publication Type:Journal Article
- Keywords:
Phenylalanine hydroxylase;
Hyperphenylalanineemia;
Phenylketonuria;
Genotype;
Phenotype
- From:
Chinese Journal of Medical Genetics
2025;42(6):648-659
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the spectrum of genetic variants and phenotypes of Phenylalanine hydroxylase deficiency (PAHD) in Lianyungang area and the correlation between genotype and phenotypes among the patients.Methods:Eighty children with Hyperphenylalaninemia (HPA) diagnosed at the Lianyungang Branch of Jiangsu Provincial Newborn Screening Center between January 2015 and December 2022 were enrolled. Peripheral blood samples were collected for genetic analysis using next generation sequencing (NGS), Sanger sequencing, and multiplex ligation-dependent probe amplification (MLPA) to identify the variants of PAH gene. Clinical and phenotypic data were concurrently analyzed to investigate the correlation between the types of PAH gene variant and phenotypes. This study was approved by the Medical Ethics Committee of Lianyungang Maternal and Child Health Care Hospital (Ethics No.: XM2022041). Results:① PAH variants were identified in 93.75% (75/80) of the children, classified as PAHD cases, while 6.25% (5/80) harbored PTS variants. ② Of the 150 PAH alleles from 75 PAHD children, a total of 152 variants (55 distinct types) were detected, with a detection rate of 100%. 80.26% (122/152) were located in exons, with the main types of variants were missense variants (67.11%, 102/152). 53.29% (81/152) of coding sequence variants occurred in the PAH gene catalytic center region of PAH protein, while 19.74% (30/152) of variants involved non-coding sequences. ③The phenotypes of the 75 PAHD children were evenly distributed. The rescreening Phe concentrations and Phe/Tyr ratios of classic-phenylketonuria (CPKU) and mild-phenylketonuria (MPKU) patients were markedly higher than initial screening values ( P<0.001, P<0.001; P=0.004, P=0.016). The genotypes of the PAHD patients mostly occurred as compound heterozygotes, and different mutation positions and variant types significantly affect the phenotype ( P=0.042, P=0.045). ④APV/GPV genotype-phenotype analysis of 61 patients showed high consistency between predicted and actual phenotypes ( κ=0.755, P<0.001). Conclusion:PAH variants were detected in the most of HPA children in Lianyungang area. The location and type of PAH variants were related to the severity of the phenotype, and the non-coding sequence variants and non-missense variants may aggravate the phenotype, and the APV/GPV model predicted the phenotype was highly consistent with the actual phenotype.
