EFS CpG island analysis showing tissue-specific degrees of methylation. (A) Map of the EFS promoter and exon1/exon2 region. CGI 131 (GRCh37/Hg19, black bar), which encompasses 144 CpG positions, overlaps with the EFS transcription start site (TSS). The analyzed region covers 260 bases of the CGI containing 27 CpG dinucleotides and is located upstream of the EFS TSS. The first analyzed CpG position is not part of the CGI (GRCh37/hg19). (B) Detailed methylation analysis of samples showing partial EFS methylation as determined by sequence analysis of cloned PCR products from one buccal swab sample, cultured uveal melanocytes and UM sample T10. Each row of boxes represents the CpGs of an individual PCR product. Each column represents a specific CpG in the analyzed region. Allelic discrimination was facilitated by an informative SNP (rs3759609). White boxes, unmethylated CpGs; black boxes, methylated CpGs; n.d., methylation state was not determined.