Question to the Department of Health and Social Care:

To ask the Secretary of State for Health and Social Care, how many children diagnosed with metachromatic leukodystrophy since the approval of gene therapy treatment have been assessed as ineligible for treatment because diagnosis occurred after symptoms developed.

Libmeldy, the gene therapy treatment for metachromatic leukodystrophy (MLD) has been funded nationally by NHS England since 2022 and is delivered exclusively through the specialist children’s service at Royal Manchester Children’s Hospital. Information on referrals and clinical eligibility decisions for patients who do not proceed to treatment is held by the hospital and is not collected centrally by NHS England.

We recognise the importance of people living with a rare disease receiving the right diagnosis as early as possible. The Government is committed to improving the lives of those living with rare diseases, such as MLD, under the UK Rare Diseases Framework. We published the fifth annual England action plan in February 2026, where we report on the steps we have taken to advance the priorities of the framework, including getting a final diagnosis faster. The Generation Study is now underway in selected National Health Service hospitals and is screening for more than 200 rare genetic conditions, including MLD. By identifying affected babies earlier, the study has the potential to enable faster diagnosis and access to specialist care and treatment.