SETBP1 and Schinzel-Giedion syndrome: MRD29 is characterized by mild or moderate mental retardation and growth retardation, with most reported variants being frameshift and nonsense variants in SETBP1, while SGS is characterized by growth retardation, special facial features, and multiple deformities, among others, and most reported variants are missense variants in SETBP1 with a typical variant hotspot in the fourth exon.