text: Mutations in emerin cause X-linked recessive Emery–Dreifuss muscular dystrophy, which is characterized by early contractures in the Achilles tendons, elbows and post-cervical muscles; muscle weakness proximal in the upper limbs and distal in lower limbs; along with cardiac conduction defects that range from sinus bradycardia, PR prolongation to complete heart block. In these patients, immunostaining of emerin is lost in various tissues, including muscle, skin fibroblasts, and leukocytes, however diagnostic protocols involve mutational analysis rather than protein staining. In nearly all cases, mutations result in a complete deletion, or undetectable levels, of emerin protein. Approximately 20% of cases have X chromosomes with an inversion within the Xq28 region.
  Moreover, recent research have found that the absence of functional emerin may decrease the infectivity of HIV-1. Thus, it is speculated that patients with Emery–Dreifuss muscular dystrophy may have immunity to or show an irregular infection pattern to HIV-1.