GM2 gangliosidosis in a UK study of children with progressive neurodegeneration: 73 cases reviewed

Aim To report the demographic, phenotypic, and time‐to‐diagnosis characteristics of children with GM2 gangliosidosis referred to the UK study of Progressive Intellectual and Neurological Deterioration. Method Case notification is made via monthly surveillance card, administered by the British Paediatric Surveillance Unit to all UK‐based paediatricians; children with GM2 gangliosidosis were identified from cases satisfying inclusion in the UK study of Progressive Intellectual and Neurological Deterioration and analysed according to phenotypic and biochemical categories. Results Between May 1997 and January 2010, 73 individuals with GM2 gangliosidoses were reported: 40 with Tay–Sachs disease, 31 with Sandhoff disease, and two with GM2 activator protein deficiency. Together they account for 6% (73/1164) of all diagnosed cases of progressive intellectual and neurological deterioration. The majority (62/73) were sporadic index cases with no family history. Children of Pakistani ancestry were overrepresented in all subtypes, particularly juvenile Sandhoff disease, accounting for 10 of 11 notified cases. Infantile‐onset variants predominated (55/73); the mean age at onset of symptoms was 6.2 and 4.7 months for infantile‐onset Tay–Sachs and Sandhoff disease respectively, and 26.2 and 34.7 months for the corresponding juvenile‐onset variants. Time to diagnosis averaged 7.4 months and 28.0 months in infantile‐ and juvenile‐onset disease respectively. Interpretation GM2 gangliosidosis is a significant cause of childhood neurodegenerative disease; timely diagnosis relies upon improved clinical recognition, which may be increasingly important as specific therapies become available. There is a potential benefit from the introduction of screening programmes for high‐risk ethnic groups.