To exclude structural alterations in the PRKCA protein as a potential cause for MS, we sequenced the coding regions (including 30–50 bases of exon–intron boundaries) and 1.700 bases of the promoter of the PRKCA gene in ten unrelated Finnish MS patients, of which five had at least one copy of the putative disease allele (rs887797–rs1010544: C-A). Here, PRKCA is linked to myeloid sarcoma.