Geographical Clustering of Juvenile Onset Systemic Lupus Erythematosus within the Sultanate of Oman.

OBJECTIVE While SLE is found worldwide, there is diversity in clinical presentation of the disease according to geographical variations. The aim of this study is to describe geographical distributions of childhood onset SLE within Oman to identify geographical clustering and to compare the demographic, clinical, and immunological characteristics of this cluster against the rest of Oman. METHODS We retrospectively reviewed the hospital charts of 104 consecutive children with childhood onset SLE who were seen in pediatric rheumatology centers in the Sultanate of Oman over a 15-year period between 1995 and 2010. RESULTS Geographical clustering of childhood onset SLE was identified in Sharqiya region, which constituted 41% (n=43) of all cases in Oman. This cohort of patients had characteristic disease features which consisted of significantly more boys affected with SLE compared to the rest of the country (42% versus 15%; p=0.002). These children also tended to be younger (10.3 versus 16.5 years; p=0.001), diagnosed at an earlier age (6.4 versus 9.4 years; p<0.001) with a stronger family history of SLE (58% versus 33%; p=0.010). These children also had increased incidence of mucocutanous changes (81% versus 62%; p=0.036) and decreased hematological abnormalities (30% versus 51%; p=0.036). CONCLUSION We identified geographical clustering of childhood onset SLE to Sharqiya region in Oman which is associated with unique demographical and clinical features. Whether increased prevalence of disease in this region is due to geographical, environmental, ethnic or genetic factors is yet to be determined. However, it is likely to be interplay of known and other unrecognized factors.