Bi-allelic mutations in ERCC6 (excision repair cross-complementing 6), a family member of ERCC4 (FANCQ), lead to Cockayne syndrome (CS, OMIM #133540) characterized by severe growth and developmental retardation, progressive neurological dysfunction and symptoms of premature aging (Falik-Zaccai et al. 2008), while heterozygous pathogenic variants result in non-syndromic POI (Qin et al. 2015). This evidence concerns the gene ERCC4 and Cowden syndrome 1.