RNASET2-deficient Cystic Leukoencephalopathy

What else is it called?

  • Cystic leukoencephalopathy without megalencephaly
  • Leukoencephalopathy with bilateral anterior temporal lobe cysts

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What causes it?

This condition is believed to be caused by defects in the RNASET2 gene. This gene provides the body with instructions to produce a protein called ribonuclease T2 which is an enzyme commonly referred to as ribonuclease. This ribonuclease is commonly found within regions of the brain and in the lysosomes of the cell. These lysosomes help with the break-down of foreign objects and aid immune response. Ribonuclease help to break down another protein called RNA, this is very similar to DNA in its genetic makeup. It is thought that due to the defect in the gene means that RNA cannot be broken down completely. This may lead to a build-up of the substance that is being broken down in the lysosomes which interferes with brain and myelin development. Research suggests that ribonuclease T2 may also have a role in the development of new blood vessels [Angiogenesis] and also in supressing certain cancer growths. Further research is still being carried out into the role of these proteins.

How common is it?

Current literature suggests that at least 50 individuals have been diagnosed with this condition worldwide. Of these 50, only 25% have been proven to have the gene mutation for RNASET2-deficient cystic leukoencephalopathy.

What are the signs and symptoms?

Symptoms may first present at birth, however this can differ per person. More common signs and symptoms of this condition are:

  • Uncontrolled muscle tension
  • Involuntary eye movements
  • Seizures
  • Deafness
  • Intellectual disability
  • Abnormalities in inner ear
  • Poor social contact
  • Brain infections
  • Delay in the development of crawling and walking and other motor functions

If you are diagnosed with this condition, it is common to develop abnormalities within the white matter of the brain. The white matter of the brain contains nerves and tissue, it also contains a layer of fatty sheath called myelin which covers the nerve fibres. With this condition, it may be that myelin is not properly developed which may leave nerves in the brain unprotected. This can lead to a loss of motor function such as walking and crawling.

How is it diagnosed?

A physical examination with the expression of symptoms and an MRI scan may be used to diagnosis this condition. The MRI scan would be used to detect the abnormalities of the brain which are associated with this condition. Urine and blood samples may also be used to detect any abnormalities with your metabolism.

Due to overlapping of clinical symptoms with other conditions, it is important that this condition is diagnosed with genetic testing. Your health care professional will speak with you more about this if it thought that you may have this condition.

Can it be treated?

Information for treatment for this condition is very limited, this may be due the rarity of this condition. The treatment that is available is aimed at managing symptoms as they present such as seizures and abnormalities in inner ear.

Do my family need to be tested?

RNASET2-deficient cystic leukoencephalopathy can only be passed on to a child if both parents have a copy of the faulty gene. This is called autosomal recessive inheritance. A person who has a copy of the faulty gene is known as a carrier.

If both parents are carriers, their child has a one in four (25%) chance of inheriting the disorder, and a one in two chance (50%) of being a carrier. This is the same for each child the parents have.

If the child only inherits one copy of the faulty gene, they will be a carrier but will not have the disorder. In some rare cases, carriers have had mild symptoms of the disorder for which they carry the faulty gene.

Once you are diagnosed, you can speak to a genetic counsellor. They can explain how you may have inherited RNASET2-deficient cystic leukoencephalopathy. They can also tell you about genetic testing for the rest of your family. They can provide advice and support if you go on to have children of your own.

If you have previously had a child with RNASET2-deficient cystic leukoencephalopathy and go on to have further children, their New-born Screening test should be carried out within 24-48 hours of birth.

Relevant Organisations


References are available on request. Please contact Helen Morris by phoning 0845 241 2173 or emailing helen@metabolicsupportuk.org [Resource Library No: AAP002].

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