Abstract
AIM: To study the neurodegenerative diseases that cause progressive intellectual and neurological deterioration (PIND) in children in the UK. METHOD: This active prospective epidemiological study asked UK paediatricians to notify all childhood cases of PIND via the British Paediatric Surveillance Unit. Clinical data were obtained using a questionnaire or via a site visit. An independent PIND study Expert Group classified the cases. RESULTS: Between May 1997 and April 2024 (27 years), 2373 children with PIND were identified who had an underlying diagnosis to explain their deterioration. There were six cases of variant Creutzfeldt-Jakob disease plus 2367 children (1265 males, 1102 females) with other diseases. The lifetime risk of having a diagnosed disease causing PIND was 0.1 in 1000 live births. Asian British children made up 28.6% of the 2183 cases with known ethnicity. Excluding variant Creutzfeldt-Jakob disease, diagnosed children had 259 diseases, identified before death in 99% of children (only 39 were known to have had postmortems). Increasingly, diagnosis was made using genetic studies. Sixty-one per cent (157 of 259) of the diseases were inborn errors of metabolism, affecting 78% of diagnosed children. There were 43 lysosomal diseases. INTERPRETATION: This unique epidemiological study of many rare childhood neurodegenerative diseases provides valuable practical information about the presentation, clinical features, and inheritance of these complex disorders.