A variant of the HLA-DRB1 gene — called HLA-DRB1*03 — appears to predispose people to developing multiple sclerosis (MS) in childhood, and to correlate with greater disease activity among those who do, a study in Greek patients suggests.
The research also points to a protective role of one other variant of this gene, HLA-DRB1*11, which was significantly less common in pediatric-onset MS patients than in the general population.
These findings were detailed in “HLA-DRB1 allele impact on pediatric multiple sclerosis in a Hellenic cohort,” a study published in the Multiple Sclerosis Journal – Experimental, Translational and Clinical.
The HLA-DRB1 gene provides instructions for making a protein with a critical role in immune system activation. It is essentially found at the surface of certain immune cells, where it tells other immune system cells what their targets are, helping them to distinguish invaders from the body’s own cells.
Given its role in immunity, variants of this gene have been shown to influence the risk of MS in adults, with the HLA-DRB1*15:01 variant increasing nearly three times this risk, and variants like HLA-DRB1*16 protecting people from the disease. (A gene variant describes any change — benign or disease-causing — in the DNA sequences that compose a gene.)
Studies in pediatric-onset MS (POMS) patients are more scarce, but also point to associations between HLA-DRB1 gene variants and disease risk. But whether these variants also influence disease course and age at onset remains unknown.
A team led by researchers at the National and Kapodistrian University of Athens examined a group of 50 patients of Greek origin with pediatric-onset MS (mean age at onset, 15.3). Most had relapsing-remitting disease (39 patients), and the remaining 11 had secondary progressive MS.
Using blood samples from each patient, the team assessed which HLA-DRB1 gene variants were present. Because every person has two copies of the HLA-DRB1 gene (one inherited from the mother, and one from the father), patients could either have two copies of same variant, or one copy of two distinct variants.