Other rare 11p15.5-related molecular defects, such as maternal duplications, CDKN1C and IGF2 point mutations affecting the maternal allele and the paternal allele, respectively, have also been implicated in SRS, as well as HMGA2 and PLAG1 mutation or deletion, two genes which form part of a pathway with IGF2 (28). This evidence concerns the gene IGF2 and Silver-Russell syndrome.