Juvenile systemic lupus erythematosus in multicase families from Saudi Arabia: comparison of clinical and laboratory variables with sporadic cases.

The object of this study was to compare patients with familial versus sporadic systemic lupus erythematosus (SLE) with respect to clinical, laboratory variables and outcome. The familial SLE group comprised 12 patients while the comparative group comprised 24 patients selected by systemic sampling from our pediatric rheumatology clinic database. Those patients are listed according to the date of referral, which represents a sampling frame. The first patient was chosen randomly and subsequent patients were chosen at intervals of three. The two groups were compared with respect to: demographic information, age of onset of SLE, disease and follow up duration, clinical and laboratory variables and outcome. The patients from the familial group were younger and had an earlier age of onset of disease (P = 0.03, 0.001 respectively). Seven patients with familial SLE were from the eastern region of Saudi Arabia (P = 0.006). The two groups were comparable with respect to gender, disease duration and follow-up. At diagnosis, the discoid rash was more frequent in the familial group (P = 0.03) while other clinical and laboratory variables including disease activity as measured by SLEDAI did not show significant differences. The mean dose of steroid and use of other immunosuppressive therapy were similar in both groups. Three patients from the familial group died; two of them had unusual complications (one patient had transverse myelitis and pancreatic pseudocyst and the other one had extensive pyoderma gangrenosum). All patients from the sporadic group are alive in stable condition but one patient had severe central nervous system disease. Familial SLE patients tend to be younger and more likely to have discoid rash, in addition a marked difference in the origin of patients was noted. These differences may be helpful in identifying SLE patients with a stronger genetic predisposition. The mortality among familial SLE patients is more frequent which may reflect the disease severity.