Walker-Warburg syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 26, 2016
StartDiseasesWalker-Warburg syndrome

Walker-Warburg syndrome (WWS) affects the skeletal muscles of an infant's body. These are the muscles an individual uses during the process of movement. When babies have this condition, their muscle tone is very weak (hypotonia). Their muscle weakness will only increase as they get older. WWS also affects an infant's brain and eyes

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Definition & Facts

WWS is a referred to as congenital muscular dystrophy. It is a genetic disorder. It is known to impacts an infant's eyes, muscles, and brain. An infant with this condition will experience muscle atrophy and muscle weakness at a very early time in their life.

The brain of an infant with this conditions will not possess the usual grooves and folds of a normal brain. Their brains have an irregular appearance that is bumpy. It can result in a buildup of fluid in the brain (hydrocephalus). This syndrome can change the structure of an infant's brain. It is common for those with this condition to have chronic seizures.

Symptoms & Complaints

One of the most common symptoms of WWS is brain abnormalities as well as muscle atrophy and abnormal eye function. The symptoms of WWS are evident when a child is born. It is also possible for some of the abnormalities to be detected prior to birth.

With WWS, an infant will experience very low muscle tone. The tone of their muscles will not improve as they grow older and will only get worse. It's also possible for an infant with fixed joints to have WWS. This is a result of the shortening of the muscle fibers (contracture) in their body. It will significantly decrease movement in the area of their body where it occurs.

An infant with WWS will show signs of serious brain impairments at birth. This includes such conditions as smooth brain, enlarged ventricles in the brain and more.

They will show signs of hydrocephalus. This is a condition of an infant having excessive cerebrospinal fluid in their brain. This will cause their brain to become enlarged.

WWS can also be identified by an infant's eyes. They may have no optic nerve, or their optic nerve may be severely underdeveloped. They could have malformed retinas and more.

Causes

It has been determined that WWS is caused by genes that do not function properly. They are the genes that affect an individual's eyes, brain and muscle development. WWS is a condition that in inherited. It occurs when a person has two abnormal copies of an affected gene.

A person who has a functioning copy of a gene, as well as a copy of the gene that does not function, is a genetic carrier. The parent who is the carrier will not necessarily have any symptoms. When both parents have the abnormal gene, they have a 50 percent chance of passing it on to their children. Their children will have a 25 percent chance of not developing WWS.

Research has determined that WWS occurs with a specific lack of proteins responsible for the development of the body's muscles, brain, and eyes. With an infant has WWS, the genes in their body responsible for encoding proteins are mutated.

There are a number of known genetic causes for WWS. Genetic testing has not been able to determine the cause for WWS in every family. Researchers believe they will be able to identify more genes that are responsible for causing WWS in the future. WWS has affected children around the world. The number of males and females affected are equal. 

Diagnosis & Tests

WWS is commonly diagnosed by using a fetal magnetic resonance imaging (MRI) or medical ultrasound during the later stages of pregnancy. This diagnosis is able to be confirmed a short time after a child's birth. Clinical evaluations of infants suspected of having WWS are able to be conducted quickly. These evaluations are able to identify the characteristics of WWS. It may require a number of tests to confirm the diagnosis. The abnormalities of the brain will be determined by using an MRI.

Enlarged ventricles will be identified. This may also be done with a computed tomography (CT) scan of an infant's brain. The muscle tissue will then be examined. A biopsy of muscle tissue will be taken and used for a microscopic evaluation. Detailed eye examinations will also be conducted.

Genetic testing may be conducted. This will be able to provide molecular confirmation of a WWS diagnosis. The confirmation of WWS is determined to be present when two mutations are identified. Gene testing can be done in a number of different ways. One of the most common genetic testing methods involves exome sequencing. This method makes it possible to analyze all known genes and detect any type of mutations at once. 

Treatment & Therapy

At this time no known cure exists for WWS. Treatment and therapy are conducted on an individualized basis. The focus will be to address specific individual symptoms. In most cases, treatment will involve a coordinated efforts between a team of medical specialists. This will include neurologists, pediatricians, eye specialists, an orthopedic surgeon and a number of other medical professionals. The medical team will work together to create a comprehensive treatment plan for a child's care.

A child with WWS may be given anti-seizure medication as part of their treatment. Surgery may be performed to implant shunts in their brain to drain excess fluid and decrease any pressure that may be present.

Physical therapy may be utilized as a way to increase muscle strength. Infants with WWS are often given a feeding tube. This is done to help with any problems that may occur with feeding.

Prevention & Prophylaxis

There is no known way to prevent a child from developing WWS. Children with this condition have serious brain and muscle abnormalities. The life expectancy with any child who is born with classic WWS is never very high. Most children pass away within the first few months of life. Almost all children with classic WWS die before they reach the age of three.