Investigation of NOTCH4 coding region polymorphisms in sporadic inclusion body myositis.

The NOTCH4 gene, located within the MHC region, is involved in cellular differentiation and has varying effects dependent on tissue type. Coding region polymorphisms haplotypic of the sIBM-associated 8.1 ancestral haplotype were identified in NOTCH4 and genotyped in two different Caucasian sIBM cohorts. In both cohorts the frequency of the minor allele of rs422951 and the 12-repeat variation for rs72555375 was increased and was higher than the frequency of the sIBM-associated allele HLA-DRB1*0301. These NOTCH4 polymorphisms can be considered to be markers for sIBM susceptibility, but require further investigation to determine whether they are directly involved in the disease pathogenesis.