He was diagnosed with systemic lupus erythematosus on the basis of the following clinical features: constitutional symptoms (loss of appetite and loss of weight), postinflammatory hyperpigmentation over the upper and lower limbs, peripheral polyneuropathy, leukopenia, lymphopenia, anemia, low C3 and C4, and positive ANA, anti-dsDNA, anti-Sm, anti-RNP, and anti-Rib-P antibodies. The gene discussed is BTG3; the disease is lymphopenia.