title: [Autoimmune diseases and multiple sclerosis].
abstract: BACKGROUND
  Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system with an unknown origin, although the immunological system plays a crucial role in its pathogenesis. It has been observed that the relatives of MS patients very often have other autoimmune diseases (ADs) and it has been suggested that there may be susceptibility genes that are common to this group of diseases.
  
  
  OBJECTIVE
  Our aim was to estimate the prevalence of ADs in first and second degree relatives of patients with MS and to determine the coexistence of other ADs in MS patients.
  
  
  METHODS
  We selected 251 patients with MS defined by the Poser criteria and face-to-face interviews with the patients and/or their relatives were conducted to investigate the following ADs: MS, rheumatoid arthritis, systemic lupus erythematosus, polyarteritis nodosa, autoimmune thyroid disease (ATD), inflammatory bowel disease, myasthenia gravis, type I diabetes mellitus (DMI) and psoriasis. RESULTS. 29.9% of the patients with MS had a first and/or second degree relative with an AD. Prevalence of ADs in first degree relatives was 15.5%, 30% in familial MS and 40% if the patient had both MS and another AD. The most frequent ADs were: MS 27%, psoriasis 18%, ATD 16% and DMI 15%. 15 patients had MS and another AD: six ATD, three DMI, four psoriasis, one inflammatory bowel disease and one myasthenia gravis.
  
  
  CONCLUSIONS
  These findings lend support to the existence of susceptibility genes that are common to the different ADs and would act as risk factors.
authors.affiliation: Servicio de Neurología, Hospital de Gran Canaria Dr. Negrin, 35020 Las Palmas de Gran Canaria, Spain. malemanyr@telefonica.net
authors.forename: M J
authors.initials: MJ
authors.lastname: Alemany-Rodríguez
authors.forename: Y
authors.initials: Y
authors.lastname: Aladro
authors.forename: R
authors.initials: R
authors.lastname: Amela-Peris
authors.forename: M C
authors.initials: MC
authors.lastname: Pérez-Viéitez
authors.forename: M P
authors.initials: MP
authors.lastname: Reyes-Yáñez
authors.forename: M C
authors.initials: MC
authors.lastname: Déniz-Naranjo
authors.forename: F
authors.initials: F
authors.lastname: Sánchez-Garcia
mesh_terms: D001327:Autoimmune Diseases / Q000235:genetics* / Q000276:immunology / Q000503:physiopathology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D009103:Multiple Sclerosis / Q000235:genetics* / Q000276:immunology / Q000503:physiopathology