XRCC6 and obesity due to melanocortin 4 receptor deficiency: TNF-α downregulated some of the DNA damage repair genes, which are also altered by obesity: PARP1 (−49.3%, P = 0.008), BLM (−46.9%, P = 0.02), FEN1 (−25.5%, P = 0.04), and PCNA (−38.0%, P = 0.008) (Fig. 5A–D), but did not affect HDAC1 and Ku70 gene expression (Fig. 5E and F).