Silver-Russell syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at August 25, 2016
StartDiseasesSilver-Russell syndrome

Russell-Silver syndrome (RSS) is a congenital disorder characterized by stunted growth and limb or facial asymmetry. Russell-Silver syndrome is also known as Russell-Silver dwarfism. In countries outside the United States, it is often referred to as Silver-Russell syndrome.

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Definition & Facts

Russell-Silver syndrome is often recognizable at birth or early childhood, and symptoms tend to resolve themselves as children grow older. Prognosis for the condition is good, and there is no evidence that the condition causes a shortened lifespan. Symptoms can range from severe to so mild that they are virtually unnoticeable.

The condition was first diagnosed in 1953 and 1954 by Dr. Silver and Dr. Russell independently. While the exact number of cases is unknown, it is estimated that the condition is found in approximately 1 in 75,000 to 100,000 people.

Symptoms & Complaints

Most symptoms of the disorder are present at birth, and other symptoms may develop in early childhood. RSS is characterized by slowed growth of the fetus in-utero resulting in low birth weight and abnormally slow growth in early childhood.

Infants may have difficulty eating, and parents may notice that they rarely cry for food. Children with RSS usually continue to have diminished appetites and are very thin and small in stature. The child’s head is usually a normal size, but it may appear to be abnormally large due to the small size of the rest of the body.

Growth never catches up, and adults are typically shorter than average. Males with RSS have an average height of 151 centimeters (4 feet, 11 inches) while females average 140 centimeters (4 feet, 7 inches).

RSS may cause developmental delays such as delays in motor skills, speech delays, or cognitive deficits. Children with the condition typically have normal intelligence levels but may be slow to reach early developmental milestones. They may experience learning disabilities, attention deficit hyperactivity disorder, and autism.

Other symptoms may include asymmetry in the limbs, body, or face. Children may have a short arm span and a condition known as clinodactyly, which occurs when the pinky finger curves in towards the fourth finger.

The child’s face may have a triangular shape and display a prominent forehead, narrow chin, and small jaw. The small size of the jaw may cause difficulty chewing and speech problems. The corners of the mouth may appear to turn downwards.

Other possible symptoms include changes in skin pigment, low blood sugar (hypoglycemia), and gastrointestinal diseases. In rare cases, the condition may be associated with congenital heart defects. It should be noted that children affected by the disorder are unlikely to display all of the symptoms and the severity of symptoms varies greatly.

Causes

RSS is caused by very rare genetic mutation, and most people with the condition have no family history of the disorder. It is unusual for a family to have more than one child who is affected by RSS. In approximately 60 percent of patients, abnormalities on chromosomes 7 and 11 have been linked with the condition. In the other 40 percent of cases, the cause remains unknown or idiopathic. There is some evidence that pregnancy after the age of 35 has been linked to children being born with RSS.

Diagnosis & Tests

Due to the rarity of the disorder, many physicians are unfamiliar with the condition and may have difficulty with diagnosis. Genetic testing can sometimes diagnose the condition, but a negative test result does not rule out clinical diagnosis of the disorder.

Treatment & Therapy

If a physician suspects that a child may have RSS, a highly experienced RSS specialist may be needed. Throughout the course of treatment, a child may need to be seen by a variety of specialists including a geneticist, gastroenterologist, nutritionist, and endocrinologist.

Although symptoms usually diminish and eventually cease with age, ongoing monitoring and testing will be needed to help to ensure that children develop as normally as possible. Blood glucose monitoring should be performed regularly to monitor for hypoglycemia.

Limb length is often monitored to check for asymmetry and overall growth rates will need to be tracked. Parents should be vigilant and keep their own records regarding children’s physical and mental development.

Children who have been diagnosed with RSS should receive medical treatment as soon as possible. Best results occur when children are treated from birth, and they will need to be under the supervision of specialists throughout their childhood. Since there is no cure, the focus is on managing symptoms and helping to encourage development and growth.

A regimented nutrition plan with specific scheduled eating and snack times is often helpful in order to prevent malnutrition and hypoglycemia. If a child does not receive sufficient calories or suffers from low blood sugar it can cause problems with brain development and worsen stunted growth.

Doctors may recommend growth hormone therapy and hormone-releasing treatments. Growth hormones have been found to stimulate children’s height so that they are closer to that of a child not suffering from RSS. Limb asymmetry in the legs can be treated with shoe lifts, and in extreme cases corrective surgery may be recommended.

Children who are having difficulty maintaining weight may not do well in surgical situations. For this reason, surgery should be performed only if the child is healthy enough to endure it.

Children with RSS are likely to have a variety of special needs. Development issues are often treated with speech therapy, physical therapy, and language therapy, and early development intervention programs.

It is important that parents interact with children according to their age rather than their size. A child will develop better psychologically and socially if he or she is dressed in age-appropriate clothing and is expected to display appropriate behavior and responsibility.

Prevention & Prophylaxis

Since RSS is a genetic disorder that appears to occur randomly, there is no real way to prevent it. The chance of passing the condition on to children is low but should be considered. Individuals who have been diagnosed with the condition may wish to consult with a genetic counselor before planning to have children.