In PLOS Genetics this week, a University of Chicago-led team searches for genetic factors influencing inorganic arsenic metabolism and toxicity in a population from Bangladesh with potential exposure to the carcinogen through contaminated drinking water. The researchers used exome arrays to search for non-synonymous alterations influencing arsenic metabolism in 1,660
Bangladeshi participants in the "Health Effect of Arsenic Longitudinal Study," uncovering a protein-coding variant in the histidine catabolism enzyme-coding gene FTCD that appeared to coincide with decreased conversion to a demethylated form of inorganic arsenic in urine samples. That variant also appeared to correspond with arsenic-induced skin lesions in 2,401 individuals with that condition and nearly 2,500 without, the authors report, noting that FTCD's known role in one-carbon/folate metabolism "provides new evidence supporting the well-established hypothesis that the folate/one-carbon cycle plays an important role in arsenic-related disease."
For another PLOS Genetics paper, an international group led by investigators in the UK describes a germline variant in the cell adhesion molecule-coding gene DSCAM that was linked to mast cell tumor risk in retriever dog breeds. The researchers began with a genome-wide association study meta-analysis based involving 105 Labrador Retrievers with mast cell tumors and 85 unaffected controls, identifying a suspicious region spanning 2.9 megabases on chromosome 31. They focused on that region further with a second, larger meta-analysis that included 173 cases and 112 controls, along with targeted sequencing in half a dozen Labs with mast cell tumors and as many without. The search led to a mast cell tumor susceptibility variant that was subsequently tested and verified in case-control sets of Labrador Retrievers and Golden Retrievers.
Upstate Medical University researchers present a next-generation sequencing-based approach for identifying potential blood-based microRNA markers for acute myeloid leukemia in PLOS One. The team demonstrated the veracity of its miRNA isolation, purification, and sequencing protocol with peripheral blood samples from 10 newly-diagnosed, untreated individuals with AML and nine unaffected controls, identifying miRNAs that seem to be over-represented in AML patients with tumors marked by specific mutations. "Our approach of global sequencing of miRs as opposed to microarray analysis removes the bias regarding which miRs to assay and has demonstrated discovery of new associations of miRs with AML," the authors write, adding that the current analysis offers new clues on leukemic clone evolution, as well as potential strategies for "monitoring relapse and developing new treatment strategies."