Analysis of systemic sclerosis in twins reveals low concordance for disease and high concordance for the presence of antinuclear antibodies

Arthritis Rheum. 2003 Jul;48(7):1956-63. doi: 10.1002/art.11173.


Objective: To examine concordance for systemic sclerosis (SSc) in monozygotic (MZ) and dizygotic (DZ) twins.

Methods: MZ and DZ twins were recruited nationwide. Zygosity was confirmed by DNA fingerprint analysis. The presence of antinuclear antibodies (ANAs) was determined using indirect immunofluorescence with HEp-2 cells as substrate. Identification of SSc-associated serum autoantibodies was performed by immunoprecipitation and double immunodiffusion. Major histocompatibility complex class II alleles were identified by polymerase chain reaction-restriction fragment length polymorphism analysis.

Results: Concordance for SSc was found to be similar in MZ and DZ twins. Overall concordance for SSc was low in the twins (4.7%). Concordance for the presence of ANAs was significantly higher in MZ twins compared with DZ twins. SSc-associated serum autoantibodies occurred exclusively in patients with SSc. The distribution of SSc-associated serum autoantibodies was similar to that observed in our large database of SSc patients. Increased HLA allele sharing was detected in DZ twins, irrespective of disease concordance.

Conclusion: These results indicate that inherited genetic factors are not sufficient to explain the development of SSc. Rather, these data indicate that inheritance may play a role in the development of serum autoantibodies in the "healthy" twin sibling of an SSc patient.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Twin Study

MeSH terms

  • Adult
  • Aged
  • Alleles
  • Antibodies, Antinuclear / blood*
  • Female
  • Histocompatibility Testing
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Scleroderma, Systemic / epidemiology*
  • Scleroderma, Systemic / genetics
  • Scleroderma, Systemic / immunology*
  • Twins, Dizygotic
  • Twins, Monozygotic


  • Antibodies, Antinuclear