Late-onset Tay−Sachs disease presenting with a neuromuscular phenotype—a case series

Abstract

Background and purpose: Tay−Sachs disease is a rare and often fatal, autosomal recessive, lysosomal storage disease. Deficiency in β-hexosaminidase leads to accumulation of GM2 ganglioside resulting in neuronal swelling and degeneration. Typical onset is in infancy with developmental regression and early death. Late-onset Tay−Sachs disease (LOTS) is extremely rare, especially in the non-Ashkenazi Jewish population, and is characterized by a more indolent presentation typically encompassing features of cerebellar and anterior horn cell dysfunction in addition to extrapyramidal and neuropsychiatric symptoms. Cases: A case series of four unrelated patients of non-Ashkenazi Jewish origin with a predominantly, and in some cases pure, neuromuscular phenotype with evidence of a motor neuronopathy on electromyography is presented. Cerebellar atrophy, reported to be a ubiquitous feature in LOTS, was absent in all patients. Conclusion: This case series provides evidence to support a pure neuromuscular phenotype in LOTS, which should be considered in the differential diagnosis of anterior horn cell disorders.