Metachromatic Leukodystrophy (MLD)
https://pmc.ncbi.nlm.nih.gov/articles/PMC12130617
Metachromatic leukodystrophy (MLD) is a rare genetic disease that affects the brain. The earlier it is diagnosed, before the onset of neurological symptoms, the better the chances of successful treatment. This study examined real-world data to assess diagnostic delays and identify early clinical signs. Researchers analysed large US claims datasets and identified 174 probable MLD cases (born after 2017) defined by using the MLD-specific International Classification of Disease (ICD-10-CM) E75.25 diagnosis code. They found that the median time between the first coded symptom and the diagnosis was 658 days, with only 8% of the cases diagnosed within the recommended window for treatment eligibility. Developmental delays, seizures, gastrointestinal and ophthalmologic concerns were commonly reported several months before diagnosis. A natural-history study on 47 early-onset MLD patients showed similar patterns, confirming the presence of early clinical features. The authors conclude that better awareness of early signs and newborn screening could help identify MLD sooner and enable timely access to the existing therapies. However, these findings rely on ICD coding without genetic confirmation, with the possibility of misclassification and under coding.