Is There a Familial Risk to Scleroderma? Save

A recent report analyzed 23,658,577 subjects in a national insurance database and found 1891 systemic sclerosis (SSc) patients. Using 21,009,551 parent–child relationships and 17,168,340 full sibling pairs they estimated the familial risks of SScm autoimmune diseases and familial transmission.

The prevalence of SSc in the general population was 0.008 %.

Among the first-degree relative with SSc, there were 3 people with SSc with a calculated a prevalence of 0.08 %. The adjusted relative risk for SSc was 81.21 (95%CI, 11.40–579.72) for siblings of SSc patients.

The familial transmission (genetic plus shared environmental contribution to total phenotypic variance of SSc) was 0.72. However, 84.1 % of patients were expected to be sporadic cases. The RR (95 % CI) in first-degree relatives of SSc patients was 2.64 (1.46–4.75) for rheumatoid arthritis, 6.51 (4.05–10.46) for systemic lupus erythematosus, 2.77 (1.04–7.35) for Sjögren’s syndrome, 8.05 (2.03–31.92) for idiopathic inflammatory myositis, and 1.52 (1.15–2.01) for psoriasis.

The risk of SSc and other autoimmune diseases was increased in relatives of SSc subjects. These analyses suggested that genetic/family factors explain over two-thirds of the phenotypic variance of the disease.