Achalasia in a patient with adult-onset Tay-Sachs disease

Natural History of Adult Patients with GM2 Gangliosidosis

OBJECTIVE

GM2 gangliosidoses are lysosomal diseases due to biallelic mutations in the HEXA (Tay-Sachs disease [TS]) or HEXB (Sandhoff disease [SD]) genes, with subsequent low hexosaminidase(s) activity. Most patients have childhood onset, but some experience the first symptoms during adolescence/adulthood. This study aims to clarify the natural history of adult patients with GM2 gangliosidosis.

METHODS

We retrospectively described 12 patients from a French cohort and 45 patients from the literature.

RESULTS

We observed 4 typical presentations: (1) lower motoneuron disorder responsible for proximal lower limb weakness that subsequently expanded to the upper limbs, (2) cerebellar ataxia, (3) psychosis and/or severe mood disorder (only in the TS patients), and (4) a complex phenotype mixing the above 3 manifestations. The psoas was the first and most affected muscle in the lower limbs, whereas the triceps and interosseous were predominantly involved in the upper limbs. A longitudinal study of compound motor action potentials showed a progressive decrease in all nerves, with different kinetics. Sensory potentials were sometimes abnormally low, mainly in the SD patients. The main brain magnetic resonance imaging feature was cerebellar atrophy, even in patients without cerebellar symptoms. The prognosis was mainly related to gait disorder, as we showed that beyond 20 years of disease evolution, half of the patients were wheelchair users.

INTERPRETATION

Improved knowledge of GM2 gangliosidosis in adults will help clinicians achieve correct diagnoses and better inform patients on the evolution and prognosis. It may also contribute to defining proper outcome measures when testing emerging therapies. ANN NEUROL 2020;87:609-617.

Dysarthria and Stutter as Presenting Symptoms of Late-Onset Tay-Sachs Disease in Three Siblings

Late-onset Tay-Sachs disease (LOTS) is a rare autosomal-recessive genetic disorder caused by insufficient activity of the lysosomal enzyme, beta-hexosaminidase A, resulting in intracellular accumulation of gangliosides in the central nervous system. Clinical manifestations can include unsteadiness in gait, muscle weakness, cognitive dysfunction, psychiatric disturbance, and dysarthric speech. The variable presentation of these symptoms, combined with the late onset of the disease, often results in misdiagnosis. We present video of 3 sibling cases of LOTS in which a dysarthric stutter was the sole presenting symptom in order to better characterize the phenotype of this disease.