RESUMEN
Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease characterized by the production of a wide range of autoantibodies, resulting in tissue damage. Although the susceptibility to SLE has been attributed to complex interactions between genetic and environmental factors, the influence of a genetic predisposition to SLE is supported by observations of familial aggregations. Family studies have found that siblings with an SLE-affected relative have a 20-fold higher risk of developing SLE compared with the general population. Here, we present a rare case of two male siblings with SLE. The clinical, laboratory, and histopathological findings of these individuals showed the characteristic features of SLE. Human leukocyte antigen (HLA) typing revealed that the brothers and their mother shared the common HLA haplotype of DRB1*1501 and DQB1*0602, which is significantly associated with disease susceptibility in both family-based and casecontrol studies. This report provides an opportunity to reveal the role of genetic factors in the development of SLE.