Vitamin D deficiency was demonstrated in 48.3% of euthyroid HT, 35% of newly diagnosed HT, 20.5% of controls. Serum 25(OH)D levels were correlated with thyroid volume (r= 0.15), anti-TPO (r= -0.36), anti-Tg levels (r= -0.34). The gene discussed is TG; the disease is vitamin D deficiency.