What Is Russell-Silver Syndrome?

Russell-Silver syndrome (RSS), sometimes called Silver-Russell syndrome (SRS), is a congenital condition. It is characterized by stunted growth and limb or facial asymmetry. Symptoms range over a broad clinical spectrum from severe to so mild that they go undetected.

The disorder is caused by very rare genetic defects. The number of cases in the global population is estimated to be between 1 in 3,000 and 1 in 100,000.

In addition, diagnosis can be difficult because many physicians may not be familiar with the disorder. Medical specialists can aid in diagnosing the condition and deciding on a treatment plan.

Treatment is focused on managing the symptoms of RSS. As patients grow older, many symptoms will improve. People with RSS who plan to have children should consult a genetic counselor beforehand. The odds of passing the condition on are low, but should be considered.

There are many symptoms of Russell-Silver syndrome. Most are present at birth, while others appear in early childhood. Most people with RSS have normal intelligence, but they may experience delays in reaching early developmental milestones.

The major criteria for RSS are:

  • intrauterine growth retardation/ small stature at birth (below the 10th percentile)
  • after-birth growth below average for length or height (below the 3rd percentile)
  • normal head circumference (between the 3rd and 97th percentile)
  • limb, body, or facial asymmetry

Minor symptoms include:

  • short arm span, but normal upper-to-lower-arm-segment ratio
  • fifth-finger clinodactyl (when the pinky fingers curve toward the fourth fingers)
  • triangular-shaped face
  • prominent forehead

Other symptoms that may occur with RSS include:

  • changes in skin pigment
  • hypoglycemia (low blood sugar levels)
  • feeding difficulties (in infants)
  • gastrointestinal disorders (acute diarrhea, acid reflux disease, etc.)
  • motor, speech, and/or cognitive delay

Rare cases have been associated with:

  • cardiac defects (congenital heart disease, pericarditis, etc.)
  • underlying malignant conditions (e.g., Wilms’ tumor)

Most people who have RSS don’t have a family history of the disease.

About 60 percent of RSS cases are caused by defects on a particular chromosome. About 7-10 percent of RSS cases are caused by maternal uniparental disomy (UPD) of chromosome 7, in which the child receives both number 7 chromosomes from the mother, instead of one chromosome 7 from each parent.

However, for most people with RSS, the underlying genetic defect is undetermined.

Your doctor may need to consult with multiple specialists to make a diagnosis. Signs and symptoms of RSS are most prominent in infancy and early childhood, making diagnosis even more difficult in older children. Ask your doctor for a referral to a specialist for a more in-depth analysis of your condition.

Medical specialists that you and your doctor may want to consult include:

  • geneticist
  • gastroenterologist
  • nutritionist
  • endocrinologist

RSS may be mistakenly diagnosed as:

  • Fanconi anemia syndrome (a genetic defect in DNA repair known to cause cancer)
  • Nijumegen breakage syndrome (a genetic disorder causing a small head, short stature, etc.)
  • Bloom syndrome (a genetic disorder causing short stature and increased likelihood of cancer)

RSS is present at birth. The first few years of life are very important in child development. Treatment for RSS focuses on treating its symptoms so the child can develop as normally as possible.

Treatments to help with growth and development include:

  • a nutrition schedule with specified snack and meal times
  • growth hormone injections
  • luteinizing hormone-releasing treatments (a hormone released in females to trigger monthly ovulation)

Treatments to correct and accommodate limb asymmetry include:

  • shoe lifts (inserts used to slightly raise one heel)
  • corrective surgery

Treatments to encourage mental and social development include:

  • speech therapy
  • physical therapy
  • language therapy
  • early development intervention programs

Children with RSS should receive regular monitoring and testing. This can help ensure they meet developmental milestones. Most people with RSS will see their symptoms improve as they enter adulthood.

Symptoms of RSS that should improve with age include:

  • speech difficulties
  • low weight
  • short stature

Tests to monitor development include:

  • blood glucose testing for hypoglycemia
  • growth velocity (used to follow child’s growth throughout childhood)
  • measurement of limb length for asymmetry

RSS is a genetic disorder, and a person with RSS only rarely passes it on to their children. Individuals with this disorder should consider visiting a genetic counselor. A counselor can explain the odds that your child could develop RSS.