All four patients with variants in the genes responsible for SRS (IGF2, CDKN1C, and PLAG1) had a diagnosis of “clinical SRS.” However, only two out of five patients with variants in causative genes for known genetic syndromes had a diagnosis of “clinical SRS.” Patients 1 and 2 with IGF2 variants showed motor and intellectual developmental delay, genital features, and high NH-CSS score (≥ 5/6) including feeding difficulties[12]. This evidence concerns the gene CDKN1C and Silver-Russell syndrome.