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Pelizaeus-Merzbacher disease: developing a new way to study and eventually treat this disabling, rare disease of childhood

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What did the project achieve?

“We have successfully corrected a gene fault in cells from a patient with Pelizaeus-Merzbacher disease (PMD) and shown that this can restore myelin production in a laboratory model,” says Professor Rowitch of the University of Cambridge. “Our results then led us to uncover existing drugs that may offer an effective new treatment for children with PMD.”

Children with this rare condition have gene faults that affect the myelin sheath that protects nerve cells in the brain and spinal cord and helps them to transmit nerve impulses. This can have devastating consequences and, with no cure, children with the most severe form of PMD are likely to lose their lives at a young age.

Professor Rowitch’s team used cutting-edge gene-editing technologies to correct the genetic fault in a living system and in cells taken from a patient with PMD – demonstrating that this approach could restore myelin production as well as developing a better understanding of the biology behind the disease.

“We identified the exact point in development when the cells with the faulty gene were dying – just as they reach their myelin-producing stage,” explains Professor Rowitch.

This discovery helped them to pinpoint the likely biological cause of cell death, leading them towards a type of existing drug that could offer protection.

“We then showed that these drugs could help cells with the faulty gene to evade death and boost myelin production,” says Professor Rowitch.

Based on these encouraging results, Action Medical Research has recently awarded more funding to the team to continue with this exciting research.

“If our results continue to show promise, we aim to take the most promising drug into a clinical trial involving patients with PMD as soon as possible,” says Professor Rowitch.

This research was completed on

Children with a rare, genetic condition called Pelizaeus-Merzbacher disease (PMD) may one day benefit from research by Professor David Rowitch of the University of Cambridge. Children with PMD can experience a range of disabling symptoms, including muscle stiffness, difficulties with movement, balance and speech, and delayed learning. Sadly, there’s no cure and children with the most severe forms of the disease often lose their lives before their 10th birthday. Professor Rowitch is in the early stages of developing a new way to study and eventually treat PMD – a type of “gene editing” therapy – which he hopes will one day improve children’s lives.

How are children’s lives affected now?

The symptoms of PMD vary from one child to another. Some babies’ symptoms start at birth or during the first few weeks of life. Babies’ eyes can move repeatedly from side to side, or up and down, in an uncontrolled way (‘nystagmus’). They can have laboured or noisy breathing, and unusually floppy or stiff muscle tone. Babies can also be late to reach developmental milestones.

PMD usually affects boys (estimates suggest between two and five of every million males have the disease1) and the severity of PMD varies. Sadly, some children lose their lives while still young, while other people with the disease have lived to their sixties.

“Rehabilitative care and treatments for spasticity in the muscles help children with PMD, but there’s no cure” says Professor Rowitch. “In my experience, children’s parents are, quite understandably, desperate to find more effective therapies.”

How could this research help?

“PMD is a genetic disease,” says Professor Rowitch. “We are in the early stages of developing a new treatment for PMD – a form of ‘gene editing’ – which we hope will one day improve children’s lives.”

Children with PMD have changes – or mutations – in a particular gene, which stop a substance called myelin from being made and from wrapping properly around nerve fibres. Myelin normally protects nerve fibres and allows messages to travel along them. A lack of myelin is thought to be the underlying cause of all the symptoms children experience.

The team believes that using gene editing to correct the mutated gene may enable children’s cells to make myelin properly. It may also be possible to use modified cells with corrected genes to perform laboratory tests to find out whether any existing drugs might benefit children with PMD. In this project, the researchers are using skin cells from children with PMD to find out whether gene editing shows promise in the laboratory. If it does, it may one day benefit children with PMD and other similar diseases.


1. Genetics Home Reference. Pelizaeus-Merzbacher disease. http://ghr.nlm.nih.gov/condition/pelizaeus-merzbacher-disease Website accessed 25 January 2016.




Project Leader Professor David H Rowitch MD PhD
Project Team Professor Robin JM Franklin BVetMed PhD
Project Location Wellcome Trust-MRC Stem Cell Institute, University of Cambridge
Project duration One year
Date awarded 25 November 2015
Project start date 1 December 2016
Project end date 30 November 2017
Grant amount £69,604
Grant code GN2431


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