Definition of Russell-Silver syndrome:

Russell-Silver syndrome is a disorder present at birth that involves poor growth, low birth weight, short height, and differences in the size of the two sides of the body.

Causes, incidence, and risk factors:

An estimated 7 - 10% of patients with this syndrome have a defect called the maternal uniparental disomy (UPD) for chromosome 7. In another 35% of patients, there is an abnormality on chromosome 11 that affects genes important in growth. However, a cause cannot be identified in most patients. Most cases occur in people with no family history of the disease.

The estimated number of people who develop this condition varies greatly. Some say it affects about 1 in 3,000 people. Other reports say it affects 1 in 100,000 people. Males and females are equally affected.