The methyl-CpG binding protein-2 gene (MECP2 on Xq28) is located on the long arm of X. This gene correlates with RETT syndrome and the premature ovarian failure gene POF (POF1: Xq21→qter, POF2: Xq13.3→Xq21.1) [10]. This evidence concerns the gene FMR1 and atypical Rett syndrome.