In PLOS One, researchers in Spain present findings from an exome sequencing-based analysis of Angelman syndrome (AS)-related phenotypes, uncovering a wider gene set than reported in the past. The team did exome sequencing on 14 individuals with AS-like clinical features — such as developmental delay, seizures, hyperactivity, and an upbeat disposition — who had not yet received a molecular diagnosis of AS or another condition. The search led to pathogenic or likely pathogenic variants in 10 genes involved in synaptic, chromatin remodeling, transcriptional regulation, and other neurodevelopmental pathways, along with the heat shock factor-coding gene HSF2. "Our results highlight the wide genetic heterogeneity in AS-like patients and expands the differential diagnosis," the authors report, suggesting that parent-child exomes may help to diagnose additional AS-like conditions. "A high rate of diagnosis is essential since it contributes to more appropriate clinical surveillance as well as family genetic counseling."
A team from Bangladesh, Vietnam, the UK, and Australia retraces genetic epidemiological features found in Salmonella Paratyphi A isolates at surveillance sites in Bangladesh. As they report in PLOS Neglected Tropical Diseases, the investigators did whole-genome sequencing on more than five dozen S. Paratyphi A isolates collected at eight locations between 2008 and 2018, phylogenetically analyzing the genomes alongside more than 200 S. Paratyphi A isolates sequenced in the past. "Our genomic data revealed that the population structure of S. Paratyphi A in Bangladesh [is] comprised of only previously defined lineages A, C, and F," they report, "and carried [a] single point mutation in [a] gyrA gene associated with decreased fluoroquinolone susceptibility with no evidence of multi-drug resistance."
Researchers in Brazil explore SARS-CoV-2 diversification and spread in Brazil for a paper appearing in PLOS Neglected Tropical Diseases. By sequencing 185 SARS-CoV-2 isolates from north, northeast, and southeast Brazil, the team identified, tracked, and retraced the ancestry of Brazilian representatives from the SARS-CoV-2 P.1, P.2, and P.7 lineages, along with a new lineage that convergently contains a spike protein mutation found in other lineages. "[T]he recurrent report of many novel SARS-CoV-2 genetic variants in Brazil could be due to the absence of effective control measures resulting in high SARS-CoV-2 transmission rates," the authors report, adding that "our findings provided a landscape of the critical state of SARS-CoV-2 across Brazil and confirm the need to sustain continuous sequencing of the SARS-CoV-2 isolates worldwide in order to identify novel variants of interest and monitor for vaccine effectiveness."