Aided by extensive protein mutations, the SARS-CoV-2 Omicron (B.1.1.529) variant overtook the previously dominant Delta variant and rapidly spread around the world. It was shown to exhibit significant resistance to current vaccines and evasion from neutralizing antibodies. It is therefore critical to investigate the Omicron mutations trajectories. In this study, a literature search of published articles and SARS-CoV-2 databases was conducted, We explored the full list of mutations in Omicron BA.1, BA.1.1, BA.2, and BA.3 lineages. We described in detail the prevalence and occurrence of the mutations across variants, and how Omicron differs from them. We used GISAID as our primary data source, which provides open access to genomics data of the SARS-CoV-2 virus, in addition to epidemiological and geographical data. We examined how these mutations interact with each other, their co-occurrence and clustering. Our study offers for the first time a comprehensive description of all mutations with a focus on non-spike mutations and demonstrated that mutations in regions other than the Spike (S) genes are worth investigating further. Our research established that the Omicron variant has retained some mutations reported in other SARS-CoV-2 variants, yet many of its mutations are extremely rare in other variants and unique to Omicron. Some of these mutations have been linked to the transmissibility and immune escape of the virus, and indicate a significant shift in SARS-CoV-2 evolution. The most likely theories for the evolution of the Omicron variant were also discussed.

Human herpes virus 6A (HHV-6A) is able to integrate into the telomeric and subtelomeric regions of human chromosomes representing chromosomally integrated HHV-6A (ciHHV-6A). The integration starts from the right direct repeat (DRR) region. It has been shown experimentally that perfect telomeric repeats (pTMR) in the DRR region are required for the integration, while the absence of the imperfect telomeric repeats (impTMR) only slightly reduces the frequency of HHV-6 integration cases. The aim of this study was to determine whether telomeric repeats within DRR may define the chromosome into which the HHV-6A integrates. We analysed 66 HHV-6A genomes obtained from public databases. Insertion and deletion patterns of DRR regions were examined. We also compared TMR within the herpes virus DRR and human chromosome sequences retrieved from the Telomere-to-Telomere consortium. Our results show that telomeric repeats in DRR in circulating and ciHHV-6A have an affinity for all human chromosomes studied and thus do not define a chromosome for integration.

Lopes–Maciel–Rodan syndrome (LOMARS) is an extremely rare disorder, with only a few cases reported worldwide. LOMARS is caused by a compound heterozygous mutation in the HTT gene. Little is known about LOMARS pathogenesis and clinical manifestations. Whole exome sequencing (WES) was performed to achieve a definitive molecular diagnosis of the disorder. All NGS-identified variants underwent the Sanger confirmation. In addition, a literature review on genetic variations in the HTT gene was conducted. The paper reports a case of LOMARS in a pediatric patient in Russia. A preterm girl of non-consanguineous parents demonstrated severe psychomotor developmental delays in her first 12 months. By the age of 6 years, she failed to develop speech but was able to understand everyday phrases and perform simple commands. Autism-like behaviors, stereotypies, and bruxism were noted during the examination. WES revealed two undescribed variants of unknown clinical significance in the HTT gene, presumably associated with the patient’s phenotype (c.2350C>T and c.8440C>A). Medical re-examination of parents revealed that the patient inherited these variants from her father and mother. Lopes–Maciel–Rodan syndrome was diagnosed based on overlapping clinical findings and the follow-up genetic examination of parents. Our finding expands the number of reported LOMARS cases and provides new insights into the genetic basis of the disease.