A revised estimate of twin concordance in systemic lupus erythematosus

Authors

  • Dennis Deafen DrPH,

    Corresponding author
    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
    • USC School of Medicine, 1420 San Pablo PMB B104, Los Angeles, CA 90033
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  • Agustin Escalante MD,

    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
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  • Lisa Weinrib MD,

    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
    Current affiliation:
    1. Maricopa Medical Center, Phoenix, AZ)
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  • David Horwitz MD,

    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
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  • Barbara Bachman BS,

    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
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  • Pradip Roy-Burman,

    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
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  • Ann Walker PhD,

    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
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  • Thomas M. Mack MD

    1. Department of Preventive Medicine, the Department of Medicine, and the Department of Pathology, University of Southern California School of Medicine, Los Angeles.
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Abstract

Objective. Based on a small clinical series and previously published case reports, concordance for systemic lupus erythematosus (SLE) among monozygous (MZ) twins has been reported to be as high as 69%. Using a larger and less biased sample, we provide another estimate of this percentage.

Methods. We established a registry of twins with SLE, based upon self-reports and information provided by the patients' physicians. We used DNA fingerprinting to validate the reported zygosity in a sample of these twins.

Results. Of 107 twin pairs meeting the American College of Rheumatology 1982 revised criteria for the diagnosis of SLE, 24% of 45 MZ pairs and 2% of 62 dizygous (DZ) pairs were concordant. The frequency distributions of diagnostic criteria and disease symptoms in the SLE patients were similar to those in other published reports of SLE patients. Zygosity was confirmed by DNA fingerprinting in a subsample of 15 self-described MZ twins and 7 self-described DZ twins. AH individuals had correctly predicted their zygosity.

Conclusion. MZ concordance for SLE is similar to that for other autoimmune diseases and is much lower than previously believed.

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