Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, there have been a few variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), one of which is the Omicron variant (B.1.1.529). The Omicron variant is the most mutated SARS-CoV-2 variant, and its high transmissibility and immune evasion ability have raised global concerns. Owing to its enhanced transmissibility, Omicron has rapidly replaced Delta as the dominant variant in several regions. However, recent studies have shown that the Omicron variant exhibits reduced pathogenicity due to altered cell tropism. In addition, Omicron exhibits significant resistance to the neutralizing activity of vaccines, convalescent serum, and most antibody therapies. In the present review, recent advances in the molecular and clinical characteristics of the infectivity, pathogenicity, and immune evasion of Omicron variant was summarized, and potential therapeutic applications in response to Omicron infection were discussed. Furthermore, we highlighted potential response to future waves and strategies to end the pandemic.

Objective. Hypocomplementemic urticarial vasculitis syndrome (HUVS) is characterized by recurrent urticaria along with dermal vasculitis, arthritis, and glomerulonephritis. Systemic lupus erythematosus (SLE) develops in >50% of patients with HUVS, although the pathogenesis is unknown. The aim of this study was to identify the causative DNA mutations in 2 families with autosomal-recessive HUVS, in order to reveal the pathogenesis and facilitate the laboratory diagnosis.Methods. Autozygosity mapping was combined with whole-exome sequencing.Results. In a family with 3 affected children, we identified a homozygous frameshift mutation, c.289_ 290delAC, in DNASE1L3. We subsequently identified another homozygous DNASE1L3 mutation leading to exon skipping, c.320؉4delAGTA, in an unrelated family. The detected mutations led to loss of function, via either nonsense-mediated messenger RNA decay or abolished endonuclease activity, as demonstrated by a plasmid nicking assay.Conclusion. These results show that HUVS is caused by mutations in DNASE1L3, encoding an endonuclease that previously has been associated with SLE.

Chromosome 4q deletion syndrome (4q- syndrome) is a rare condition, with an estimated incidence of 1 in 100,000. Although variable, the clinical spectrum commonly includes craniofacial, developmental, digital, skeletal, and cardiac involvement. Data on the genotype-phenotype correlation within the 4q arm are limited. We present detailed clinical and genetic information by array CGH on 20 patients with 4q deletions. We identified a patient who has a ∼465 kb deletion (186,770,069-187,234,800, hg18 coordinates) in 4q35.1 with all clinical features for 4q deletion syndrome except for developmental delay, suggesting that this is a critical region for this condition and a specific gene responsible for orofacial clefts and congenital heart defects resides in this region. Since the patients with terminal deletions all had cleft palate, our results provide further evidence that a gene associated with clefts is located on the terminal segment of 4q. By comparing and contrasting our patients' genetic information and clinical features, we found significant genotype-phenotype correlations at a single gene level linking specific phenotypes to individual genes. Based on these data, we constructed a hypothetical partial phenotype-genotype map for chromosome 4q which includes BMP3, SEC31A, MAPK10, SPARCL1, DMP1, IBSP, PKD2, GRID2, PITX2, NEUROG2, ANK2, FGF2, HAND2, and DUX4 genes.