In PLOS Genetics, a team from Massachusetts General Hospital-led team searches for Huntington's disease (HD) modifiers in a cluster of Venezuelans with early onset HD. Using whole-genome sequences generated at Complete Genomics for a family of two parents and seven children, together with array-based genotypes for nearly 550 Venezuelans with or without HD, the researchers narrowed in on a genome-wide significant association with HD age of onset at a chromosome 7 locus involving the SOSTDC1 gene and two more suggestive association sites after for individual's huntingtin gene (HTT) trinucleotide expansion size. The authors went on to compare these potential modifier sites with those reported in Europeans, while more fully characterizing a HTT haplotype found in the Venezuelan population.
Members of the Epilepsy Phenome/Genome Project and the Epi4K Consortium report on rare inherited or de novo variants contributing to an epilepsy-related cortical development malformation disease called periventricular modular heterotopia (PVNH) for another paper in PLOS Genetics. By sequencing parent-child trios for 202 individuals with sporadic PVNH , the researchers uncovered 219 de novo variants in the affected children. They also tracked down four ultra-rare inherited or de novo loss of function changes in the MAP1B gene. "This work adds to a growing list of genes responsible for PVNH, illuminates new genes involved in brain development, and importantly informs us about the types of genetic variants involved in PVNH," they write.
Finally, researchers from the University of Florida and the US Navy and Marine Corps Public Health Center describe a potentially new Chikungunya virus (CHIKV) subgroup found in Haitian mosquitoes in 2016, during an arboreal surveillance program. In contrast to 2014, when their RT-PCR analyses unearthed CHIKV in small subset of the pooled Aedes aegypti mosquito samples tested, the 2016 surveillance led to CHIKV in Ae. albopictus and Culex quinquefasciatus mosquitoes. The team's subsequent sequencing and phylogenetic analyses suggested the 2016 viruses contained variants not found in the previously identified Asian lineage, falling instead in a new CHIKV subgroup within the East-Central-South African lineage.