GENE THERAPY IN THE UK NEWS

Gene therapy has recently been highlighted in the UK because of the story of sisters, Teddi and Nala whose family are affected by Metachromatic Leukodystrophy.

Children with Metachromatic Leukodystrophy are born apparently healthy but MLD gradually attacks the brain and body, leaving children unable to walk, speak, or eat and eventually unable to see or hear. Life expectancy in MLD, untreated, is between 5-8 years old.

Teddi and Nala’s story was particularly moving because the younger sister Teddi, aged 18 months has now received the gene therapy for MLD but the older sister, Nala, at the age of 3 is not a candidate for gene therapy.

After this story was in the news, we had a number of questions from families of older children and adults with Rett Syndrome who wanted to know if this might happen in Rett Syndrome, if gene therapy is shown to be effective.

Whilst it can be the case that NICE, the SMC and other relevant authorities do not approve treatments for children who are older and or those who have already deteriorated past a certain point in this kind of condition, there are some key differences between Rett Syndrome and MLD.

For example, there is no brain degeneration throughout the lifespan of a person with Rett.

Rett Syndrome is caused by mutations in the gene MECP2 This gene makes a protein which we all need for healthy brain function.

Researchers have demonstrated that bringing the protein back to mice without the protein can reverse symptoms even in late stage disease *

Researchers have also shown that removing the protein from healthy adult mice causes Rett symptoms similar to those seen in mice genetically engineered to be missing the protein.**

Whilst we move forward with caution as regards to gene therapy and the potential impact on children, young people and adults with Rett who are already symptomatic, it is also worth noting that the first GT trial currently underway is in adults with Rett Syndrome

As we move into a time where there are an increasing number of gene therapies available for neurological conditions, it’s likely that a more clear distinction will be made between diseases of brain degeneration like MLD and those of brain maintenance like Rett Syndrome.

MLD families and clinicians are now campaigning for MLD to be adding to the newborn genetic screening panel which currently screens for 9 conditions but does not currently include MLD.

Article: www.bbc.co.uk/news/health-64629680