Supplemental Data: Silver-Russell syndrome secondary to rare (epi)genotypes display diverse phenotypes and frequently do not fulfil clinical diagnostic criteria

We aimed to evaluate the suitability of SRS as an umbrella term for these (epi)genotypes by identifying key clinical features and assessing the validity of NH-CSS. An extensive literature search identified 17 CDKN1C, 21 IGF2, 17 HMGA2 and 10 PLAG1 monogenic defects. Clinical phenotypes including the NH-CSS criteria were interrogated to assess (dis)similarity between the molecular subgroups of SRS, including grouped imprinted (common and monogenic) and non imprinted monogenic molecular causes. The NH-CSS poorly identified monogenic SRS. The diverse clinical features of PLAG1, CDKN1C, HMGA2 and IGF2 defects hinders the clinical diagnosis, and these rarer (epi)genotypes could be considered as distinct entities.