In PLOS Genetics, researchers at the Karolinska Institute and the University of Helsinki describe two loci with apparent ties to vitamin D metabolism or supplement response, based on a genome-wide association study involving more than 750 two-year-olds from Finland. Using information at more than 686,000 directly genotyped or imputed SNPs, the team narrowed in on variants in the chromosome 4 gene GC and the CYP2R1 gene on chromosome 11 that appeared to coincide with blood serum levels of 25-hydroxyvitamin D in the 24-month-old participants, along with a signal in the GC gene that showed a potential association with the kids' response to daily supplements of vitamin D. From these and other data, the authors argued that "in [two]-year-old children vitamin D concentration, even when within the normal range, influences bone strength as children with genetic constellations associating with lower vitamin D concentration and poorer response to vitamin D supplementation also have weaker bones."
For a paper in PLOS Neglected Tropical Diseases, a team from Bolivia, Spain, and Argentina provides evidence suggesting chronic Chagas disease cases caused by the Trypanosoma cruzi parasite may be diagnosed with rapid diagnostic tests that target the immunoglobulins raised against Trypanosoma cruzi. Using samples collected from nearly 700 untreated volunteers at two Bolivian hospitals, the researchers compared standard enzyme-linked immunosorbent assay (ELISA)-based testing for Chagas disease with results from two commercial rapid diagnostic tests. The two rapid diagnostic tests had around 93 percent concordance, they report, and almost 98 sensitivity and 96 percent specificity compared to the ELISA test. "These results support the use of [rapid diagnostic tests] for the diagnosis of chronic Chagas disease in the studied region, and encourage their evaluation in other regions of Bolivia and other endemic countries," the authors write.
Chinese researchers explore mutation patterns found in Chinese women with lymphangioleiomyomatosis (LAM), a rare, metastatic neoplasm that most often affects women of childbearing age. For a paper in PLOS One, the team did genome sequencing, chromosomal microarray analyses, and/or multiplex ligation-dependent probe amplification testing on matched tumor and normal leukocyte formalin-fixed, paraffin-embedded samples from 61 Chinese patients with LAM in China, identifying dozens of new and known variants, small insertions or deletions, or copy number variants in TSC1 or TSC2 — genes previously implicated in the condition. The authors also tracked down dozens of suspicious variants in non-TSC1/2 genes, they report, providing a broader view of the genes that may have a role in LAM development and progression.