A novel truncated variant in SPAST results in spastin accumulation and defects in microtubule dynamics.

OBJECTIVE: Haploinsufficiency is widely accepted as the pathogenic mechanism of hereditary spastic paraplegias type 4 (SPG4). However, there are some cases that cannot be explained by reduced function of the spastin protein encoded by SPAST. The aim of this study was to identify the causative variant of SPG4 in a large Chinese family and explore its pathological mechanism. MATERIALS AND METHODS: A five-generation family with 49 members including nine affected (4 males and 5 females) and 40 unaffected individuals in Mongolian nationality was recruited. Whole exome sequencing was employed to investigate the genetic etiology. Western blotting and immunofluorescence were used to analyze the effects of the mutant proteins in vitro. RESULTS: A novel frameshift variant NM_014946.4: c.483_484delinsC (p.Val162Leufs*2) was identified in SPAST from a pedigree with SPG4. The variant segregated with the disease in the family and thus determined as the disease-causing variant. The c.483_484delinsC variant produced two truncated mutants (mutant M1 and M87 isoforms). They accumulated to a higher level and presented increased stability than their wild-type counterparts and may lost the microtubule severing activity. CONCLUSION: SPAST mutations leading to premature stop codons do not always act through haploinsufficiency. The potential toxicity to the corticospinal tract caused by the intracellular accumulation of truncated spastin should be considered as the pathological mechanism of SPG4.

The impact of enhanced recovery after surgery on inflammatory indicators and prognosis related to complex appendicitis in children.

Objective: To explore the application effect of enhanced recovery after surgery (ERAS) perioperative plan in the treatment of complex appendicitis in children, and further enrich the implementation plan of ERAS in the field of pediatric surgery. Method: This study selected 122 children who underwent laparoscopic complex appendectomy at Inner Mongolia Maternal and Child Health Hospital and Baotou Fourth Hospital from August 2018 to July 2022, and randomly divided them into a traditional surgery group (TS) and an enhanced recovery surgery group (ERAS). The changes of white blood cell (WBC), hypersensitive C-reactive protein (CRP), pro Calcitonin (PCT) and interleukin 6 (IL-6) before and after surgery were compared. The degree of pain, recovery time of intestinal function, length of hospital stay, hospital costs, postoperative complications and parental satisfaction were compared between the two groups. Result: The WBC and CRP levels in the ERAS group at 6 h after surgery, as well as the IL-6 levels on the 3rd day after surgery, were lower than those in the TS group. Meanwhile, the analgesic effect of ERAS group at 3 h and 6 h after surgery was better than that of TS group. And the ERAS group had a shorter postoperative first exhaust time, fewer overall hospital stays, and lower hospitalization costs. In addition, the ERAS group had high parental satisfaction during hospitalization. There was no statistically significant difference in postoperative complications between the two groups of children. Conclusion: ERAS can promote postoperative recovery of children, reduce surgical stress, save family medical expenses, alleviate the pain of children, and improve parental satisfaction. It is a safe and effective method for treating complex appendicitis in children.

A homozygous EVC mutation in a prenatal fetus with Ellis-van Creveld syndrome.

BACKGROUND: Ellis-van Creveld (EvC) syndrome, caused by variants in EVC, is a rare genetic skeletal dysplasia. Its clinical phenotype is highly diverse. EvC syndrome is rarely reported in prenatal stages because its presentation overlaps with other diseases. METHODS: A Chinese pedigree diagnosed with EvC syndrome was enrolled in this study. Whole-exome sequencing (WES) was applied in the proband to screen potential genetic variant(s), and then Sanger sequencing was used to identify the variant in family members. Minigene experiments were applied. RESULTS: WES identified a homozygous variant (NM_153717.3:c.153_174 + 42del) in EVC which was inherited from the heterozygous parents and confirmed by Sanger sequencing. Further experiments demonstrated that this variant disrupts the canonical splicing site and produces a new splicing site at NM_153717.3: c.-164_174del, which ultimately leads to a 337 bp deletion at the 3' end of exon 1 and loss of the start codon. CONCLUSION: This is the first reported case of EvC syndrome based on a splicing variant and detailed delineation of the aberrant splicing effect in the fetus. Our study demonstrates the pathogenesis of this new variant, expands the spectrum of EVC mutations, and demonstrates that WES is a powerful tool in the clinical diagnosis of diseases with genetic heterogeneity.

Estimating the burden and modeling mitigation strategies of pork-related hepatitis E virus foodborne transmission in representative European countries.

Hepatitis E virus (HEV) is an emerging zoonotic pathogen posing global health burden, and the concerns in Europe are tremendously growing. Pigs serve as a main reservoir, contributing to pork-related foodborne transmission. In this study, we aim to specifically simulate this foodborne transmission route and to assess potential interventions. We firstly established a dose-response relationship between the risk of transmission to human and the amount of ingested viruses. We further estimated the incidence of HEV infection specifically attributed to pork-related foodborne transmission in four representative European countries. Finally, we demonstrated a proof-of-concept of mitigating HEV transmission by implementing vaccination in human and pig populations. Our modeling approach bears essential implications for better understanding the transmission of pork-related foodborne HEV and for developing mitigation strategies.

Follow-up of two newborns with c.158G>A (p.Arg53His) mutation in gene and assessment of the site function.

: To investigate the clinical significance of c.158G>A mutation.: The blood phenylalanine (Phe) was continuously monitored in 2 unrelated newborns with suspected hyperphenylalaninimia (HPA) carrying c.158G>A mutation. The cross-species conservation of the mutant amino acid was analyzed using T-Coffee. Swiss-Model software was used to construct a 3D protein structure and the impact of candidate mutations on the secondary structure of the protein product was analyzed. The population carrying rate of the p.Arg53His mutation was analyzed by literature searching. Allelic phenotype values (APV) and genotypic phenotype values (GPV) were used to predict the phenotype associated with the mutation. Two mutations of gene were detected in each newborn: c.611A>G(p.Tyr204Cys), c.158G>A(p.Arg53His) and c.1238G>C(p.Arg413Pro), c.158G>A(p.Arg53His). Two children tolerated normal diet and plasma Phe levels were within the normal range during follow-up. The mother of case 2 was homozygous with p.Arg53His mutation under the condition of long-term normal diet, and the blood Phe concentration and Phe/Tyr were all within the normal range. The mutant amino acids were not highly conserved among the 13 different species. The 3D structural model showed that p.Arg53His mutation reduced the hydrogen bond from 2 to 1 between the 53rd and 49th amino acids of PAH. The allele frequency of p.Arg53His was 0.015 08 in HPA patients and 0.001 621 in normal population, while the prevalence of p.Arg53His allele was highest in the East Asian normal population (0.013 73). The APV and GPV system predicted that the mutation was related to mild HPA(MHP) type. : The different compound heterozygous mutations of p.Arg53His lead to clinical phenotype varieties. The reduction of enzyme activity caused by the mutation of p.Arg53His is not sufficient to cause symptoms of phenylketonuria, so the mutation may be "likely benign".