Chai Yuqiong, Ning Haofeng, Xia Junke, Wang Ya'nan, Kong Xiangdong
Department of Medical Genetics and Prenatal Diagnosis, Luoyang Maternal and Child Health Care Hospital, Luoyang, Henan 471000, China.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2024 Jun 10;41(6):702-707. doi: 10.3760/cma.j.cn511374-20220426-00282.
To explore the characteristics of phenylalanine hydroxylase (PAH) gene variants and prenatal diagnosis for 43 Chinese pedigrees affected with Phenylketonuria (PKU).
Forty three PKU pedigrees diagnosed at the First Affiliated Hospital of Zhengzhou University between 2019 and 2021 were selected as the study subjects. Variants of the PAH gene of the probands were screened by high-throughput sequencing, and candidate variants were verified by Sanger sequencing. Negative cases were further analyzed by multiplex ligation-dependent probe amplification (MLPA) to detect large fragment deletions and duplications of the PAH gene. For 43 women undergoing subsequent pregnancy, Sanger sequencing, MLPA, combined with short tandem repeats (STR) sequence-based linkage analysis, were carried out for prenatal diagnosis.
Among the 86 alleles carried by the 43 probands, 78 nucleotide variants (90.70%) and 3 large deletions (3.49%) were found based on high-throughput sequencing and MLPA. The 81 mutant alleles had included 21 missense variants, 5 splice site variants, 4 nonsense variants, 2 microdeletions, 1 insertional variant and 2 large fragment deletions. Relatively common variants have included p.Arg243Gln (23.26%), p.Arg111Ter (8.14%), EX6-96A>G (6.98%), p.Val399Val (5.81%) and p.Arg413Pro (4.65%). Most of the variants were located in exons 7, 11, 3, 6 and 12. For the 43 families undergoing prenatal diagnosis, 9 fetuses (20.45%) were diagnosed with PKU, 20 (45.45%) were heterozygous carriers, and 15 (34.09%) did not carry the same pathogenic allele as the proband. All neonates were followed up till 6 months old, and the accuracy of prenatal diagnosis was 100%.
The combination of high-throughput sequencing, Sanger sequencing, MLPA and linkage analysis can increase the diagnostic rate of PKU and attain accurate prenatal diagnosis.
探讨43个中国苯丙酮尿症（PKU）家系的苯丙氨酸羟化酶（PAH）基因变异特征及产前诊断情况。
选取2019年至2021年在郑州大学第一附属医院确诊的43个PKU家系作为研究对象。通过高通量测序筛查先证者的PAH基因变异，并用桑格测序验证候选变异。对阴性病例进一步采用多重连接依赖探针扩增（MLPA）检测PAH基因的大片段缺失和重复。对43例后续妊娠的女性，采用桑格测序、MLPA并结合基于短串联重复序列（STR）的连锁分析进行产前诊断。
43例先证者携带的86个等位基因中，基于高通量测序和MLPA发现78个核苷酸变异（90.70%）和3个大片段缺失（3.49%）。81个突变等位基因包括21个错义变异、5个剪接位点变异、4个无义变异、2个微缺失、1个插入变异和2个大片段缺失。相对常见的变异包括p.Arg243Gln（23.26%）、p.Arg111Ter（8.14%）、EX6 - 96A>G（6.98%）、p.Val399Val（5.81%）和p.Arg413Pro（4.65%）。大多数变异位于外显子7、11、3、6和12。对43个进行产前诊断的家系，9例胎儿（20.45%）被诊断为PKU，20例（45.45%）为杂合子携带者，15例（34.09%）未携带与先证者相同的致病等位基因。所有新生儿随访至6个月龄，产前诊断准确率为100%。
高通量测序、桑格测序、MLPA和连锁分析相结合可提高PKU的诊断率并实现准确的产前诊断。
