Genetically and clinically heterogeneous disorder characterized by low birth weight, postnatal growth retardation, facial dysmorphism, bilateral body asymmetry, and clinodactyly of the fifth fingers. Alterations in GENETIC IMPRINTING are involved. Hypomethylation of IGF2/H19 locus near an imprinting center region of chromosome 11p15 plays a role in a subset of Silver-Russell syndrome. Hypermethylation of the same chromosomal region, on the other hand, can cause BECKWITH-WIEDEMANN SYNDROME. Maternal UNIPARENTAL DISOMY for chromosome 7 is known to play a role in its etiology.