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).
Silver Russell Syndrome [SRS], or Russell Silver Syndrome [RSS/SRS] is a rare disorder characterized by intrauterine growth retardation and postnatal growth deficiency along with a handful of common physical characteristics and a range of other symptoms. The incidence is unknown but is estimated at 1 per every 30,000 to 100,000 live births. The wide spectrum of phenotype findings vary both in incidence rate and severity from one individual to another. Besides prenatal and postnatal growth retardation, the most common characteristics are normal head circumference (appearing large for the body) at BIRTH , a large forehead that protrudes out from the plane of the face, a triangular-shaped face, a pinky that is shaped in a curved position (clinodactyly), lack of appetite/low BMI, and undergrowth of one side or limb(s) of the body (hemihypotrophy), resulting in unequal (asymmetric) growth. The majority of children with RSS/SRS fall within the normal range of intelligence, but are more likely to have motor and speech delays; this can vary by the child’s genetic cause. Intervention at an early age (infancy) is critical. RSS/SRS is genetically heterogeneous, meaning that different genetic abnormalities are believed to cause the disorder. Abnormalities affecting certain genes on chromosomes 7 or 11 have been found in up to 60-70% of RSS/SRS patients, leaving approximately 30-40% of patients where the underlying cause of RSS/SRS is not known and the patient must be clinically diagnosed.
Causes
One in 10 children with this syndrome has a problem involving chromosome 7. In other people with the syndrome, it may be due to a problem with chromosome 11. Most of the time, it occurs in people with no family history of the disease. The estimated number of people who develop this condition varies greatly. Males and females are equally affected.
Genetic abnormalities of certain genes that control growth have been found to cause the condition. Russell-Silver syndrome has been linked to a genetic change in chromosomes 7 or 11 in about 60% of people with the condition. However, in about 40% of people clinically diagnosed with the condition, no genetic cause has been found. Changes involving chromosomes other than 7 and 11 may cause the condition. Researchers continue to study other genetic changes that could lead to this disorder.
Symptoms
Signs of Russell-Silver syndrome vary widely from child to child. The condition can affect many different parts of your child’s body. Common signs of the condition may include:
- Large head for body size, wide projecting forehead with a small triangle-shaped face and small, narrow chin
- Curving of the pinky toward the ring finger
- Failure to thrive, including delayed bone age
- Low birth weight
- Short height, short arms, stubby fingers and toes
- All or part of one side of the body is smaller than the other side (asymmetry)
- Stomach and intestine problems such as acid reflux and constipation
Diagnosis
Genetic testing can identify the two known causes of SRS: 11p15 loss of methylation (also known as H19 mutation), and Maternal UniParental Disomy of chromosome 7 (MUPD7). It is thought that these two variations of SRS count for around 60% of children with SRS. For the remaining 40% a clinical diagnosis is gained through the identification of typical SRS characteristics.
Treatment
The multiple medical problems connected to SRS means treatment be via a range of specialists and early intervention programmes. This might include medication to stimulate appetite, the use of a gastronomy tube for feeding, glucose infusions and daily growth hormone injections. There may also be the need for intervention plans from physiotherapists, speech therapists and corrective surgeries.
