背景:苯丙氨酸羟化酶缺乏症(PAHD)是一种常染色体隐性遗传疾病,由苯丙氨酸羟化酶(PAH)基因突变引起的影响苯丙氨酸(Phe)代谢。它具有复杂的表型,在各种群体中具有许多变体和基因型。本研究着手分析银川市苯丙酮尿症(PKU)儿童的筛查结果,并表征PAH基因的突变变异。
方法:对2017年1月至2021年12月银川市不同妇产医院出生的398,605例新生儿苯丙酮尿症筛查结果进行回顾性分析。遗传代谢疾病的筛查是在父母同意的情况下自费进行的。通过将串联质谱(MS/MS)发现与临床表现进行综合诊断。高通量测序(HTS)用于检测经临床诊断和自愿测试的PKU儿童的遗传和代谢疾病相关基因。通过Sanger测序和亲本验证验证鉴定的基因座。
结果:在筛查的新生儿中,诊断出45例(11.3/100,000)PKU。在进行自费PAH测序的38个案例中,在76条染色体中检测到56个突变,总体检出率为73.7%。所有病人都有突变基因,检测到的56个突变代表14个变异,包括8个错义突变,2个剪接突变,2个无意义的突变,和2个沉默突变。突变主要分布在外显子2、3、6、7、9、11和内含子4中,在外显子7中观察到的频率最高(25[44.7%])。其次是外显子11(15[26.7%])。最普遍的突变是外显子7-p。R252W(10[17.9%])和外显子7-p。R261Q(8[14.3%])。
结论:银川市PKU患儿PAH基因突变主要集中在外显子6、7、11,观察到p.R252W和p.R261Q突变检出率最高。
Phenylalanine hydroxylase deficiency (PAHD) is an autosomal recessive disorder affecting phenylalanine (Phe) metabolism caused by mutations in the phenylalanine hydroxylase (PAH) gene. It has a complex phenotype with many variants and genotypes in various populations. This study sets out to analyze the screening results of children with
phenylketonuria (PKU) in Yinchuan City and characterize the mutation variants of the PAH gene.
Phenylketonuria screening results were retrospectively analyzed in 398,605 neonates (207,361 males and 191,244 females) born in different maternity hospitals in Yinchuan City between January 2017 and December 2021. Screening for genetic metabolic diseases was performed with parental consent at their own expense. A comprehensive diagnosis was performed by integrating tandem mass spectrometry (MS/MS) findings with clinical presentations. High-throughput sequencing (HTS) was used to detect genetic and metabolic disease-associated genes in children with PKU who were clinically diagnosed and voluntarily tested. The identified loci were validated through Sanger sequencing and parental verification.
Among the screened newborns, 45 (11.3/100,000) PKU cases were diagnosed. In the 38 cases that underwent self-financed PAH sequencing, 56 mutations were detected in 76 chromosomes, with an overall detection rate of 73.7%. All patients harbored mutant genes, and the 56 mutations detected identified represented 14 variants, including 8 missense mutations, 2 splicing mutations, 2 nonsense mutations, and 2 silent mutations. The mutations were primarily distributed in exons 2, 3, 6, 7, 9, 11, and intron 4, with the highest frequency observed in exon 7 (25 [44.7%]), followed by exon 11 (15 [26.7%]). The most prevalent mutations were exon 7-p.R252W (10 [17.9%]) and exon 7-p.R261Q (8 [14.3%]).
The PAH gene mutations in children with PKU in Yinchuan City are predominantly concentrated in exons 6, 7, and 11, with the highest detection rates observed for p.R252W and p.R261Q mutations.