Russell-Silver syndromeDefinition: Russell-Silver syndrome is a disorder present at birth and diagnosed no later than early childhood. It is characterized by poor growth demonstrated by low birth weight and short stature (adult height usually less than 5 feet) and, frequently, asymmetry in the size of the two halves or other parts of the body. The facial features may have a characteristic appearance: - triangular shape with broad forehead
- small pointed chin
- thin wide mouth
Children with Russell-Silver syndrome are at risk for developmental and motor delays as well as learning disabilities.
Alternative Names: Silver-Russell syndrome; Silver syndrome
Causes, incidence, and risk factors: There is no one cause known for this rare disorder. Most cases are sporadic, that is, occur as an isolated finding in a family with no other affected family member. The features associated with Russell-Silver syndrome have been described in association with many genetic abnormalities such as: - chromosome rearrangements
- uniparental disomy (UPD) 7
- autosomal dominant and recessive families (rarely reported)
More than 400 cases have been reported. Estimates of incidence range from as high as 1 in 3,000 to as low as 1 in 100,000. Males and females are equally affected.
Symptoms: - low birth weight
- poor growth during infancy and childhood
- proportionally short stature with normal skeleton and frequently delayed bone age
- normal head circumfrence, often with the appearance of "pseudohydrocephalus"
- typical facial characteristics include a broad, prominent forehead with small triangular face and small, narrow chin
- limbs of differing lengths
- fifth finger clinodactyly (curving of the pinky toward the ring finger)
- brachydactyly (short, stubby fingers and toes)
- cafe-au-lait (coffee with milk) colored spots
- arm span less than height (short arms)
Signs and tests: The following genitourinary problems may be present: - Hypospadias (abnormality where the urethra exits the body underneath the penis, rather than at the tip) and cryptorchidism (undescended testes)
- Kidney anomalies, such as:
- hydronephrosis
- renal tubular acidosis
- posterior urethral valves
- horseshoe kidney
The following gastrointestinal disorders may be present: - Gasroesophageal reflux disease
- Esophagitis
- Food aversion
- Failure to thrive
There are no specific laboratory tests for the diagnosis of Russell-Silver syndrome. Tests may be performed as follows: - Blood sugar
- Growth hormone
- Skeletal survey, to exclude skeletal dysplasia, which may mimic Russell-Silver syndrome
- tests to determine chromosome abnormalities
- test to determine if bone age is delayed
It is estimated that 7-10% of patients with RSS have a defective gene (maternal uniparental disomy for chromosome 7). The great majority of patients with RSS to date have no identifiable cause for their diagnosis.
Treatment: The predominant treatment goals pertain to stature and growth. - growth hormone replacement may be helpful if a growth hormone deficiency is discovered
- optimal calorie intake
- early intervention
- physical therapy
- special education
Expectations (prognosis): Older children and adults do not show typical features as clearly as infants or younger children. Intelligence may be normal, although the patient may have a learning disability.
Complications: - self esteem and emotional problems related to appearance
- chewing or speaking difficulty if jaw is very small
- learning disablities
Calling your health care provider: Many specialists may be involved in treatment depending upon the physical features and developmental concerns. - Clinical geneticist to help with the diagnosis of Russell-Silver syndrome.
- Gastroenterologist or nutritionist to optimize caloric intake and enhance growth and feeding therapy.
- Developmental evaluation places the patient in early intervention, special education programs, physical therapy and occupational therapy as early as possible.
- Endocrinologist to consider the use of a growth hormone when the child is school-aged.
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