The patients who developed NC showed no difference in biochemical characteristics at presentation and follow-up, however, their PTH levels at the 3rd year were higher (145 vs. 78 pg/mL, p=0.002), and they had higher treatment dose of both phosphate and calcitriol (p<0.05) (Table 5, Table 6). The gene discussed is PTH; the disease is nevus comedonicus syndrome.