Late-onset Tay–Sachs disease (LOTS) is a rare lysosomal storage disorder caused by deficient beta-hexosaminidase A (HEXA) activity. Toxicity results from the accumulation of gangliosides in the central nervous system. In juvenile-onset forms, patients present in childhood with progressive incoordination and/or developmental regression; in the “chronic” or “adult-onset” forms, patients present from childhood through early adulthood with weakness, ataxia, dysarthria, spasticity, dystonia, tremor or psychosis. While stutter is reported accompanying other symptoms of LOTS,1 it is not reported as the sole initial manifestation. We report three patients who presented in childhood with developmental stutter, years before developing other neurological manifestations.

Patient 1: This 6-year-old girl, born to non-consanguineous parents of Ashkenazi Jewish and non-Jewish European background, was the product of an uncomplicated pregnancy and delivery. She spoke her first words at 10 months, sat independently and crawled at 7 months, and walked independently at 12.5 months. She developed a marked stutter at 3 years, fine motor delays at 4 years, and subsequent deterioration of gross and fine motor skills, social regression, cognitive decline and reduced speech output.

Neurological exam at age 6 showed poor attention, difficulty following one-step commands, sparse and dysarthric speech, tongue weakness, limb rigidity …