From OMIM
Silver-Russell syndrome-1 (SRS1) is a clinically heterogeneous condition characterized by severe intrauterine growth retardation, poor postnatal growth, craniofacial features such as a triangular shaped face and a broad forehead, body asymmetry, and a variety of minor malformations. The phenotypic expression changes during childhood and adolescence, with the facial features and asymmetry usually becoming more subtle with age. Hypomethylation at distal chromosome 11p15 (ICR1) represents a major cause of the disorder. Opposite epimutations, namely hypermethylation at the same region on 11p15, are observed in about 5 to 10% of patients with Beckwith-Wiedemann syndrome (BWS; 130650), an overgrowth syndrome (Bartholdi et al., 2009). Genetic Heterogeneity of Silver-Russell Syndrome SRS2 (618905) is caused by maternal uniparental disomy of chromosome 7. SRS3 (616489) is caused by mutation in the IGF2 gene (147470) on chromosome 11p15. SRS4 (618907) is caused by mutation in the PLAG1 gene (603026) on chromosome 8q12. SRS5 (618908) is caused by mutation in the HMGA2 gene (600698) on chromosome 12q14.  http://www.omim.org/entry/180860

From MedlinePlus Genetics
Russell-Silver syndrome is a growth disorder characterized by slow growth before and after birth. Babies with this condition have a low birth weight and often fail to grow and gain weight at the expected rate (failure to thrive). Head growth is normal, however, so the head may appear unusually large compared to the rest of the body. Affected children are thin and have poor appetites, and some develop recurrent episodes of low blood glucose (hypoglycemia) as a result of feeding difficulties. Adults with Russell-Silver syndrome are short; the average height for affected men is about 151 centimeters (4 feet, 11 inches) and the average height for affected women is about 140 centimeters (4 feet, 7 inches).

Many children with Russell-Silver syndrome have a small, triangular face with distinctive facial features including a prominent forehead, a narrow chin, a small jaw, and downturned corners of the mouth. Other features of this disorder can include an unusual curving of the fifth finger (clinodactyly), asymmetric or uneven growth of some parts of the body, and digestive system abnormalities. Russell-Silver syndrome is also associated with an increased risk of delayed development, speech and language problems, and learning disabilities.  https://medlineplus.gov/genetics/condition/russell-silver-syndrome