Article Text
Abstract
Background and aims SLE and other auto-immune diseases (AID) tend to co-aggregate in families, making positive family history a risk factor for SLE. We aimed to calculate familial aggregation of rheumatic AIDs including SLE, in lupus pro-bands and to compare familial and sporadic lupus pro-bands in our cohort.
Methods We studied families of 157 consecutive lupus pro-bands satisfying the 2012 SLICC Classification Criteria in a hospital-based, cross-sectional design, probing for 3 generation pedigree charting, clinical and investigational parameters.
Results Systemic AID was seen in 39 families with a point- prevalence of 24.8% (95% CI 18.1, 31.6) and aggregation relative risk (RR) of λ−2.48. Family history of SLE was seen in 19 families with a point- prevalence of 12.1% (95% CI 7.0, 17.2) and λ−2. Both AID as a whole and lupus alone were seen more commonly with parental consanguinity (p<0.05, Table 1) with no specific inheritance pattern. AID including lupus was seen commonly in 1st degree (64.1%–63.15% respectively) followed by 2nd degree relatives (43.5%–52.6%). Most prevalent co-existent organ-specific AID was auto-immune thyroid disease (AITD) seen in 42 (26.75%) families, which also co-existed in 27 (17.2%) lupus pro-bands. Familial aggregation in lupus pro-bands showed relatively higher percentage of affected males and lesser constitutional features (p< 0.05) than sporadic pro-bands ( Table 2 ).
Conclusions In Asian Indian lupus pro-bands, familial aggregation of rheumatic AID and Lupus alone was noted in 24.8% (RR-2.48) and 12.1% (RR-2) respectively, more so in the background of parental consanguinity.