Immunocytochemistry. The EMD-Lys37del mutation impaired nuclear localization of the mutant protein. Left panels, emerin staining (green); middle panels, chromatin staining (red); right panels, combined emerin and chromatin staining. (A) In a normal female control, nuclear membranes of exfoliated oral epithelial cells showed robust staining with an antiemerin antibody. (B) Buccal cell nuclei from an affected male exhibited lack of emerin staining. (C) A female carrier heterozygous for the Lys37del mutation demonstrated staining of about 60% of nuclear membranes. Reprinted with permission from Karst ML, Herron KJ, Olson TM: X-linked nonsyndromic sinus node dysfunction and atrial fibrillation caused by emerin mutation. J Cardiovasc Electrophysiol. 2008;19(5):510-515.