Also, defective DNA synthesis leads to activation of micro-ophthalmia associated transcription factor (MITF), which upregulates both Tyrosinase and Tyrosinase related proteins (TRP 1 and 2).16 Furthermore, hyperhomocysteinemia in B12deficiency leads to increased cysteine level augmenting melanin synthesis. This evidence concerns the gene MITF and hyperhomocysteinemia.