What Is Russell-Silver Syndrome?
Russell-Silver syndrome (RSS) is a congenital condition. It is characterized by stunted growth and limb or facial asymmetry. Symptoms range from severe to so mild they go undetected.
The disorder is caused by a very rare genetic defect. The number of cases in the global population is between 1 in 3,000 and 1 in 100,000 (Kumar, et al., 2008).
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.
Causes of Russell-Silver Syndrome
Most people who have Russell-Silver syndrome don’t have a family history of the disease.
About 7-10 percent of RSS cases are caused by a defect in a gene called the maternal uniparental disomy (UPD). It is located on chromosome 7 (Saal, 2002). Researchers believe that defect is passed from parent to child.
Genetic defects that may be responsible for RSS include:
- duplication of maternal 11p15.5 chromosome
- deletion on chromosome 7
- duplication of chromosome 7
Symptoms of Russell-Silver Syndrome
There are many symptoms of Russell-Silver syndrome. Most are present at birth, while others appear in early childhood. All people with RSS have normal intelligence, but they may experience delays in reaching early developmental milestones.
The major criteria for RSS are:
- small stature for growth age (below the 10th percentile)
- after birth height/length below the 3rd percentile
- normal head circumference (between the 3rd and 97th percentile)
- limb or facial unevenness
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.)
Rare symptoms include:
- cardiac defects (congenital heart disease, pericarditis, etc.)
- underlying malignant conditions (e.g., Wilm’s tumor)
Diagnosing Russell-Silver Syndrome
Your doctor may need to consult with multiple specialists to make a diagnosis. Symptoms of RSS become less apparent with age, making diagnosis even more difficult. Ask your doctor for a referral to a specialist for a more in-depth analysis of your condition.
Medical specialists you and your doctor may want to consult include a:
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)
Treatment for Russell-Silver Syndrome
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 hormone treatments (a hormone released in females to trigger monthly ovulation)
Treatments to correct/accommodate for 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
Outlook for People with Russell-Silver Syndrome
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 anyone with RSS can pass it on to his or her children. Individuals with this disorder should consider visiting a genetic counselor. A counselor can explain the odds that your child could develop RSS.