In PLOS Genetics, researchers from Italy, the US, and Germany dig into chromosome 15 rearrangements previously implicated in neurologic conditions. The team relied on fluorescence in situ hybridization, array-based copy number profiling, single-molecule real-time sequencing, Bionano optical mapping, and other genomic approaches to compare the chromosome 15q25 region in dozens of human HapMap participants, and in non-human primates, identifying two inversion events that they subsequently examined in more detail. From the inversion breakpoints, for example, the authors narrowed in on a now-inactivated centromere in an ancient, ancestral chromosome that underwent fission with another chromosome to form chromosome 15. "The inactivation of this centromere likely released segmental duplications from recombination repression typical of centromeric regions," they write. "We hypothesize that this increased the frequency of ectopic recombination creating a hotspot of hominid inversions where dispersed GOLGA core elements now predispose this region to recurrent genomic rearrangements associated with disease."
For a PLOS Neglected Tropical Diseases paper, a team from Cameroon, the UK, Côte d'Ivoire, and Uganda describes variants in the chromosome 2 gene IL1A and the gene IL4RN on chromosome 5 that appear to increase the risk of human African trypanosomiasis-causing Trypanosoma brucei gambiense sub-species infection in populations in southern Cameroon. The investigators narrowed in on the variants by comparing SNPs in seven candidate immune genes — including several interleukin genes — in 73 human African trypanosomiasis cases and 250 unaffected controls, all selected from the same 19 enthno-linguistic groups in Africa. From these and other findings, the authors suggest that "the association between host genetic determinants and the susceptibility of T. b. gambiense infections could vary according to the population studied."
Researchers from Seoul National University and DNA Link report on results from a genome-wide association study of coronary artery calcification in Korea for a paper in PLOS One. The team focused on asymptomatic coronary artery calcification cases, comparing genotypes in 100 symptom-less Koreans with coronary artery calcification uncovered by screening and 300 unaffected controls. The search led to a coronary artery calcification-associated SNP in the chromosome 9 gene CDKN2B-AS1, which investigators validated with testing in 1,288 more individuals. "Subsequent independent replication in large sample size and functional studies, including patients with subclinical and clinical [coronary artery disease], are required to elucidate its genetic basis and the molecular pathways underlying the pathogenesis of [coronary artery calcification] and [coronary artery disease]," the investigators note.