Genetic Variant Affects MS Severity and Relapse
Patients with OAS1 gene homozygous for A allele have faster relapse, more disease activity
MONDAY, Aug. 2 (HealthDay News) -- A variant of the oligoadenylate synthetase 1 (OAS1) gene may increase the activity of multiple sclerosis (MS) and shorten time to relapse, according to a study in the Aug. 3 issue of Neurology.
Margaret O'Brien, Ph.D., of St. Vincent's University Hospital in Dublin, Ireland, and colleagues screened for the OAS1 gene in 401 subjects with active MS, 178 subjects with relapsing-remitting MS (RRMS) receiving interferon-β, and 394 healthy subjects.
Overall, the researchers found that the OAS1 gene was weakly associated with disease susceptibility, but patients homozygous for the A allele (AA) had elevated disease activity. Among RRMS patients on interferon-β, the median time to first relapse was shorter for patients with the AA genotype compared to heterozygous patients (AG) and those homozygous for the G allele (GG). Among patients with disease activity despite interferon-β, 51 percent were AA, 47 percent were AG, and 2 percent were GG. Among patients requiring second-line therapy, 34 percent were AA, 66 percent were AG, and none were GG.
"Our results suggest that all patients beginning treatment for MS should be OAS1 genotyped. Those with the AA genotype in particular should be carefully monitored for evidence of disease activity. Change in clinical indices (relapses or disability progression) and in magnetic resonance imaging lesion load during the initial six to 12 months of first-line therapy might justify an early change to more active therapy," the authors write.
Several authors disclosed financial ties to pharmaceutical companies, and one author holds patents related to immunotherapy.