[Zellweger syndrome caused by PEX6 gene variation in 2 cases and literature review]

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.

[Application of pulmonary ultrasound in the diagnosis of COVID-19 pneumonia in neonates]

Objective: To investigate the application of pulmonary ultrasound in the diagnosis of neonatal COVID-19. Methods: In this retrospective study, the clinical data of 5 infants, who were admitted to the Department of Neonatology in Wuhan Children's Hospital from 31(st) January to 25(th) February 2020, were collected. Bedsides pulmondary ultrasound was conducted on admission, during the hospitalization, and before discharge, the result were compared with the chest X-ray or CT done at the same time. Results: Among the 5 cases who aged 1-18 days, 3 were male. The main clinical manifestations were respiratory and gastrointestinal symptoms. The pulmonary ultrasonography on admission showed abnormal pleural line and pulmonary edema of different severity in all 5 cases, presented as increase and fusion of B-line, and pulmonary interstitial syndrome; among them, one case also had a small-range consolidation. The chest CT on admission showed no obvious parenchymal infiltration in 2 cases, small strip or patchy high-density shadow in 2 cases, and ground glass change in one case. The re-examination of ultrosound during the hospitalization and at discharge showed improvement in all cases and were consistent with the chest X-ray taken at the same time. Conclusions: The main changes on the pulmonary ultrasonography in neonates with COVID-19 pneumonia are increase and fusion of B-line, abnormal pleural line, and alveolar interstitial syndrome, and may coexist with small range of pulmonary consolidation. The sensitivity of pulmonary ultrasound is higher than that of chest X-ray and CT in the diagnosis of pulmonary edema, and could be used in monitoring and evaluation of the disease.