Key differentiating factors included, versus SSc, the absence of anti–Scl-70/anticentromere antibodies and limited (non-diffuse) skin sclerosis; versus systemic SLE, the absence of malar rash, proteinuria, or anti-dsDNA/anti-Sm antibodies, with non-specific alopecia; and versus SjS, the absence of sicca symptoms or anti-SSA/SSB antibodies. The gene discussed is SSB; the disease is systemic sclerosis.