Cystic leukoencephalopathy without megalencephaly

Other Names: 

CLWM

Summary

Cystic leukoencephalopathy without megalencephaly (also known as RNAse T2-deficient leukoencephalopathy) is a disorder that affects the brain. People with cystic leukoencephalopathy without megalencephaly have neurological problems that become apparent during infancy; the problems generally do not worsen over time (progress). Most affected individuals have severe intellectual disability; muscle stiffness (spasticity); and a delay in developing motor skills such as sitting, crawling, and walking. Some do not learn to walk, and most do not develop the ability to speak. Other neurological features that can occur in cystic leukoencephalopathy without megalencephaly include hearing loss caused by abnormalities in the inner ear (sensorineural deafness), seizures, involuntary writhing movements of the hands (athetosis), uncontrolled muscle tensing (dystonia), and involuntary eye movements (nystagmus). In addition to the neurological problems associated with this disorder, some affected individuals have unusual facial features sometimes described as a "doll-like face." The neurological problems in this disorder are caused by abnormalities in the brain. People with this condition have leukoencephalopathy, an abnormality of the brain's white matter that can be detected with medical imaging. White matter consists of nerve fibers covered by a fatty substance called myelin. Myelin insulates nerve fibers and promotes the rapid transmission of nerve impulses. In people with cystic leukoencephalopathy without megalencephaly, myelin is not made in sufficient amounts during development, leading to patchy white matter abnormalities (lesions) in the brain. In addition, individuals with cystic leukoencephalopathy without megalencephaly may have cysts in regions of the brain called the temporal lobes and enlargement of the fluid-filled cavities (ventricles) near the center of the brain. The white matter lesions are primarily concentrated around the cysts and the ventricles. An abnormally small head and brain size (microcephaly) often occurs in this disorder.

About Cystic leukoencephalopathy without megalencephaly

Many rare diseases have limited information. Currently, GARD aims to provide the following information for this disease:

• Population Estimate:Fewer than 1,000 people in the U.S. have thisdisease.
• Symptoms:May start to appear as a Newborn and as an Infant.
• Cause:This disease is caused by a change in the genetic material (DNA).
• Organizations:Patient organizations are available to help find a specialist, or advocacy and support for this specific disease.
• Categories:Genetic Diseases Neurological Diseases Leukodystrophies

Genetic Mutations

Cystic leukoencephalopathy without megalencephaly is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these. Learn more about genetic diseases from the National Library of Medicine (NLM).

If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team. This tool from the Surgeon General can help you collect your family health history.

Autosomal Recessive

Autosomal means the gene involved is located on one of the numbered chromosomes. Recessive means that a child must inherit two copies of the mutated gene, one from each biological parent, to be affected by the disease. A carrier is a person who only has one copy of the genetic mutation. A carrier usually doesn't show any symptoms of the disease.

If both biological parents are carriers, there is a 25% their child inherits both copies of the mutated gene and is affected by the disease. Additionally, there is a 50% chance their child inherits only one copy of the mutated gene and is a carrier.

Learn more about inheritance patterns from the National Library of Medicine (NLM).

When Do Symptoms of Cystic leukoencephalopathy without megalencephaly Begin?

Symptoms of this disease may start to appear as a Newborn and as an Infant.

The age symptoms may begin to appear differs between diseases. Symptoms may begin in a single age range, or during several age ranges. The symptoms of some diseases may begin at any age. Knowing when symptoms may have appeared can help medical providers find the correct diagnosis.