CXXC4 gene encodes Dishevelled-binding protein, functioning as a negative regulator of WNT - beta-catenin signaling pathway. CXXC5, encoding CXXC finger (PHD domain) protein, is the paralog of CXXC4. CXXC6, MLL, DNMT1, ASXL1, ASXL2, and ASXL3 are cancer-associated genes belonging to the CXXC gene family. Here, we identified and characterized CXXC10 (CXXL4L or CXXC6L) gene by using bioinformatics. Complete coding sequence of human CXXC10 cDNA was determined by assembling AI438961 EST, AC073046.7 genome sequence, BX492895 EST, and MGC22014 5'-truncated cDNA. CXXC10 gene products derived from nucleotide positions 428-739 and 811-3624 were designated CXXC10-1 and CXXC10-2, respectively. CXXC10-1 (103 aa) was homologous to CXXC4 and CXXC6 within the CXXC domain. CXXC10-2 (937 aa) was homologous to CXXC6, and KIAA1546. Complete coding sequence of KIAA1546 cDNA was determined by assembling BF900449 EST, IMAGE3536481 partial cDNA, and KIAA1546 5'-truncated cDNA (AB046766.1). LCXH1 domain (codon 1-273 of CXXC10-2) and LCXH2 domain (codon 778-854 of CXXC10-2) were conserved among CXXC10-2, KIAA1546, and CXXC6. CXXC4 and KIAA1546 genes were closely linked in head to head manner with an interval of about 700 kb. CXXC10 locus at 2p13.1, CXXC4-KIAA1546 locus at 4q24, and CXXC6 locus at 10q21.3 were paralogous regions within the human genome. Because CXXC4 and KIAA1546 genes were located in the opposite direction, intragenetic inversion might be generated within the ancestral CXXC4-KIAA1546 locus during evolution. This is the first report on CXXC10 gene as well as on the CXXC10, CXXC4-KIAA1546, and CXXC6 paralogs.