newborn screening programme

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Metachromatic leukodystrophy

Metachromatic leukodystrophy (MLD) is a rare inherited disorder that leads to a progressive loss of physical and, later, mental skills.

It is caused by an abnormal build-up of substances called sulphatides in the nerve cells, particularly in the white matter of the brain. These substances cause damage to myelin, the insulating material which is essential for normal transmission of messages between nerves.

There are 3 types of MLD based on the age symptoms appear: late-infantile MLD, juvenile MLD, and adult MLD. The incidence of MLD in the UK is estimated at approximately 1 in 40,000 births.

UK NSC screening recommendation Based on the last UK NSC review of this condition that occurred in November 2025.

Screening is not currently recommended for this condition.

Screening for MLD is not recommended because it is not currently known if:

  • the screening test is accurate and if a suitable test cut-off level has been set
  • early treatment as a result of screening improves long-term health outcomes

The UK NSC awaits evidence from pilot studies looking into screening for MLD and from the recently implemented Norwegian screening programme.

There are limitations to the evidence base for newborn screening for rare diseases. To address this challenge, the UK NSC is working with partners to develop plans for a multi-condition in-service evaluation (ISE) within the UK newborn blood spot screening programme.

MLD has been identified as a potential candidate for inclusion in this type of evaluation, which could provide valuable information on the effectiveness of screening for the condition in UK newborns.

The proposed multi-condition ISE, termed EquipoISE, is described in more detail in this UK NSC Blog article.

Supporting documents from the 2026 review

Evidence review
This document provides the evidence on which the current UK NSC recommendation is based.

Coversheet
This document summarises the review process including the public consultation comments.

Supporting documents from the 2023 review

In 2023, the UK NSC did not recommend screening for this condition.

MLD evidence map 2023
This document investigates whether a more detailed review can be conducted based on the available evidence.

Review cycle

Date previous review completed: 2026

Next review estimated to be completed: 2029 to 2030.

To see previous evidence reviews, visit the UK NSC archive.

Organisations interested in Metachromatic leukodystrophy

These organisations have expressed interest in this recommendation and may submit responses to evidence reviews.

List of organisations

If you think your organisation should be added, please contact us.