Researchers from São Paulo University have linked a microdeletion in chromosome 15 to obsessive-compulsive disorder, as they report in PLOS One this week. Using array-based comparative genomic hybridization in their pilot study of 16 patients with early onset OCD and 12 controls, the researchers uncovered a 64 kilobase deletion in chromosome 15q13.3 from one male patient with very early onset OCD. The patient's father has the same deletion, but does not have OCD, the researchers note. Additionally, the deletion affects part of the FMN1 gene, which is involved with the glutamatergic system. This, the researchers argue, underscores the idea that a complex network of genes contributes to OCD risk, and that the glutamatergic system plays a role in the condition.
In PLOS Genetics, Stanford University School of Medicine researchers report on their targeted sequencing study of nearly 170 known and candidate amyotrophic lateral sclerosis genes in 242 sporadic ALS cases and 129 matched controls. They found an enrichment of novel and rare variants in the cases, as compared to the controls, and identified new variants within the known ALS genes and genes associated with the disease. They also confirmed the previously reported association between a SNP within the APOE gene and ALS.
University of British Columbia researchers say in PLOS Pathogens that macrophages undergo epigenetic changes when they are infected by Leishmania donovani, and that these DNA methylation alterations could be how the parasite deactivates host response. Through a genome-wide study, the researchers pinpointed some 443 CpG sites where methylation changes correlated with infection. Some of these sites, they add, are linked to regulation of JAK/STAT and MAPK signaling pathways. "We therefore propose a model whereby Leishmania induced epigenetic changes result in permanent down regulation of host defense mechanisms to protect intracellular replication and survival of parasitic cells," the UBC team says.