... genotypegroups with high, medium and low expression of MBL. Theinfluence of the X /Y allele was also determined by studying six'extended' genotype groups: YA/YA, YA/XA, XA/XA, YA/O,XA/O ... distribution of the extended MBL2 haplotypes in the 218 JRA patients wasas follows: 62 (28%) YA/YA haplotype, 51 (23%) YA/XA hap-lotype, 15 (7%) XA/XA haplotype, 56 (26%) YA/O haplotype,25 (12%) ... (YA/YA and YA/XA), medium (XA/XA and YA/O) and low(XA/O and O/O) MBL genotype expression groups [10,14].MBL deficiency has been associated with increased suscepti-bility to and severity of...