multiple sclerosis in Malta.
ABSTRACT BACKGROUND:
By comparison with the neighbouring island of Sicily, the frequency of multiple sclerosis (MS) in Malta is remarkably low.
METHODS:
To explore whether the relative rarity of MS in Malta might be the result of lower population frequencies of major histocompatibility complex susceptibility alleles, we genotyped the HLA-DRB1 locus in 77 Maltese-born patients (97% of the prevalent unrelated native cases) and 206 Maltese controls. We made comparisons with previously published data for Sicily and other European countries.
RESULTS:
The anticipated association with HLA-DRB1*15, the main susceptibility allele in most other populations, was confirmed (pc = 0.009) but, in addition, we also observed an equally strong, and apparently protective, effect of the HLA-DRB1*11 allele (pc = 0.016). In comparison with previously published data from Sicily, we found that all HLA-DRB1 risk alleles were more common in Malta, whereas HLA-DRB1*11 was slightly less common.
CONCLUSIONS:
The difference in prevalence seen between the neighbouring islands of Malta and Sicily cannot be explained by differences in background HLA-DRB1 population allele frequencies, which if anything would predict a higher rate of disease in Malta than in Sicily.
From the Health Research Board,
Dublin, Ireland (G.D.);
Department of Clinical Neurosciences,
University of Cambridge,
Cambridge, UK (T.W.Y., A.G., S.S., D.A.S.C.);
Section for Experimental Neurology,
Katholieke Universiteit Leuven,
Leuven, Belgium (A.G.);
Tissue Typing Laboratory,
Addenbrooke’s Hospital,
Cambridge, UK (C.J.T., R.S.G.); C
entral Middlesex Hospital,
London, UK (M.E.);
St. Luke’s Hospital,
Guardamangia, MSD09, Malta (A.G.-D., M.V.);
Maltese Blood Transfusion Service, Guardamangia,
MSD09, Malta (A.A.); and
Laboratory of Molecular Genetics,
Department of Physiology and Biochemistry,
Biomedical Sciences Building,
University of Malta, Msida,
MSD06, Malta (A.F.).