Based on the above observations, we continued to ask whether the suppressed blood 1,25(OH)2D levels correlated with the decreased blood IGF-1 levels and increased blood creatinine levels (kidney failure may directly impair kidney 1α-hydroxylase [22] or indirectly via increased blood FGF-23 levels [23]; therefore, blood creatinine levels were used for this analysis). The gene discussed is FGF23; the disease is kidney failure.