Although multiple human leukocyte antigen (HLA) alleles associated with multiple sclerosis (MS) risk have been identified, genotype-phenotype studies in the HLA region remain scarce and inconclusive, according to researchers. In a recent study, they investigated whether MS risk-associated HLA alleles also affect disease phenotypes and confirmed and extended previous observations linking HLA MS susceptibility alleles with disease progression and specific phenotype traits. They conducted a cross-sectional, case-control study comprising 652 patients with MS who had comprehensive phenotypic information and 455 controls. They found:

• Of the total patients with MS, 586 had no missing genetic data and were included in the cumulative HLA genetic burden (HLAGB).

• In these 586 patients (404 women [68.9%]; mean age at disease onset, 33.6 [9.4] years), HLAGB was higher than in controls.

• 619 (95.8%) had relapsing-onset MS and 27 (4.2%) had progressive-onset MS.

• No significant difference was observed between relapsing-onset MS and primary progressive MS.

Citation: Isobe N, Keshavan A, Gourraud PA, et al. Association of HLA genetic risk burden with disease phenotypes in multiple sclerosis. [Published online ahead of print May 31, 2016]. JAMA Neurology. doi:10.1001/jamaneurol.2016.0980.