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.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780350310

A revised estimate of twin concordance in systemic lupus erythematosus

Delineating the genetic basis of systemic lupus erythematosus.

Systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune multisystem inflammatory disease characterized by the production of pathogenic autoantibodies. Previous genetic studies have suggested associations with HLA Class II alleles, complement gene deficiencies, and Fc receptor polymorphisms; however, it is likely that other genes contribute to SLE susceptibility and pathogenesis. Here, we report the results of a genome-wide microsatellite marker screen in 105 SLE sib-pair families. By using multipoint nonparametric methods, the strongest evidence for linkage was found near the HLA locus (6p11-p21) [D6S257, logarithm of odds (lod) = 3.90, P = 0.000011] and at three additional regions: 16q13 (D16S415, lod = 3.64, P = 0.000022), 14q21–23 (D14S276, lod = 2.81, P = 0.00016), and 20p12 (D20S186, lod = 2.62, P = 0.00025). Another nine regions (1p36, 1p13, 1q42, 2p15, 2q21–33, 3cent-q11, 4q28, 11p15, and 15q26) were identified with lod scores ≥1.00. These data support the hypothesis that multiple genes, including one in the HLA region, influence susceptibility to human SLE.

/pdf/a-genome-wide-search-for-susceptibility-genes-in-human-2f2xvmkotl.pdf

A genome-wide search for susceptibility genes in human systemic lupus erythematosus sib-pair families

Systemic lupus erythematosus (SLE) is the prototype of human autoimmune diseases. Its genetic component has been suggested by familial aggregation (lambdas = 20) and twin studies. We have screened the human genome to localize genetic intervals that may contain lupus susceptibility loci in a sample of 188 lupus patients belonging to 80 lupus families with two or more affected relatives per family using the ABI Prism linkage mapping set which includes 350 polymorphic markers with an average spacing of 12 cM. Non-parametric multipoint linkage analysis suggests evidence for predisposing loci on chromosomes 1 and 18. However, no single locus with overwhelming evidence for linkage was found, suggesting that there are no 'major' susceptibility genes segregating in families with SLE, and that the genetic etiology is more likely to result from the action of several genes of moderate effect. Furthermore, the support for a gene in the 1q44 region as well as in the 1p36 region is clearly found only in the Mexican American families with SLE but not in families of Caucasian ethnicity, suggesting that consideration of each ethnic group separately is crucial.

Genome-Wide Screen for Systemic Lupus Erythematosus Susceptibility Genes in Multiplex Families

https://www.amjmed.com/article/0002-9343(75)90261-2/pdf

J.B. Winfield

Papers

Studies of twins with systemic lupus erythematosus: A review of the literature and presentation of 12 additional sets

Proceedings: Twin studies in systemic lupus erythematosus (SLE).