Objective: To summarize the clinical features and genetic characteristics of Zellweger spectrum disorder caused by PEX6 gene variation. Methods: This was a case series research. Clinical date and genetic results of 2 neonatal cases of Zellweger syndrome caused by PEX6 gene variation in Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology and Affiliated Hospital of Guangdong Medical University from July 2021 to July 2022 were retrospectively collected and analyzed. Literature up to August 2023 was searched from electronic databases of China National Knowledge Infrastructure (CNKI), Wanfang Data and PubMed with the combined keywords of "Zellweger syndrome" "Zellweger spectrum disorder", and "PEX6 gene" both in Chinese and English. The main clinical features and genetic characteristics of Zellweger spectrum disorder caused by PEX6 gene variation were summarized. Results: The 2 male neonates both developed clinical manifestations as dyspnea, hypotonia, feeding difficulties, enlarged fontanelle, and high palatine arch after birth. Biochemical parameters indicated elevated bile acids, and the cranial ultrasound showed the enlarged bilateral ventricles and subependymal cyst in both 2 neonates. Zellweger syndrome was confirmed by whole exome sequencing, and the results revealed PEX6 gene variation in the 2 neonates, including compound heterozygous variants c.315G>A and c.2095-3T>G, and homozygous variant c.506_507del. Case 1 was hospitalized for 5 days, and case 2 for 32 days; they both died shortly after being discharged (the specific time is unknown). Literature review found 26 patients, including 2 neonates in this study, with Zellweger spectrum disorder caused by PEX6 gene defect reported in 1 Chinese article and 11 English articles. Clinical features included hearing loss (19 cases), developmental delay (19 cases), vision impairment (19 cases), elevated very long chain fatty acids (17 cases), brain malformations (15 cases), hypotonia (12 cases), hepatic insufficiency (12 cases), distinctive facies (10 cases), and dental impairment (9 cases). Compound heterozygous variations dominated the variation types (15 cases), and the frameshift variations (16 cases) were the main pathogenic variations. Conclusions: Zellweger spectrum disorder should be considered when neonates show hypotonia, feeding difficulty, distinctive facial appearance, brain malformations and failure of hearing screening, or when older children show retinitis pigmentosa, sensorineural hearing loss, amelogenesis imperfecta and developmental delays. Detection of genetic variation in the PEX gene is crucial for definitive diagnosis.
目的： 总结PEX6基因变异致Zellweger谱系障碍患儿的临床表型和遗传学特点。 方法： 病例系列研究，回顾性分析2021年7月至2022年7月华中科技大学同济医学院附属武汉儿童医院和广东医科大学附属医院诊治的2例因PEX6基因变异致Zellweger综合征新生儿的临床资料和遗传学检测结果。并分别以“Zellweger综合征”“Zellweger谱系障碍”“PEX6基因”或“Zellweger syndrome”“Zellweger spectrum disorder”“PEX6 gene”为关键词检索中国知网、万方数据库和PubMed数据库自建库至2023年8月的中英文文献。对PEX6基因变异致Zellweger谱系障碍患儿的主要临床表现和基因型特点进行描述和总结。 结果： 2例患儿均为男性，均为新生儿，均出生后出现呼吸困难、肌张力低下、喂养困难、前囟增大、高腭弓等临床表现，实验室结果均提示胆汁酸升高，颅脑彩色超声检查均提示双侧脑室增宽、室管膜下囊肿。全外显子测序分析发现2例患儿均为PEX6基因变异，分别为复合杂合变异（c.315G>A和c.2095-3T>G）、纯合变异（c.506_507del），均诊断为PEX6基因变异致Zellweger综合征。2例患儿分别于住院第5天和第32天因家长要求出院，出院后不久（具体时间不详）均死亡。文献复习符合检索条件中文文献1篇、英文文献11篇，包括本研究2例共26例患儿。主要临床表现为听力损伤（19例）、发育迟滞（19例）、视力异常（19例）、极长链脂肪酸升高（17例）、颅脑结构畸形（15例）、肌张力低下（12例）、肝脏异常（12例）、特殊面容（10例）、牙齿损伤（9例）。变异类型中以复合杂合变异（15例）为主，致病性变异以错义变异为主（16例）。 结论： 当新生儿存在肌张力低下、喂养困难、特殊面容、颅脑结构畸形以及听力筛查未通过或年长儿存在视网膜色素变性、感音性耳聋、牙釉质损伤、发育迟滞时，需考虑Zellweger谱系障碍。基因检测发现PEX基因变异可明确诊断。.