A 23-year follow-up report of juvenile-onset Sandhoff disease presenting with a motor neuron disease phenotype and a novel variant

Clinical and genetic features of a case with juvenile onset sandhoff disease

“…Among them, cerebellar ataxia is the central nervous system symptom mostly observed in juvenile SD (Table 2 ). Apart from the above five cardinal symptoms, patients could manifest with other varied clinical presentations, ranging from clinical signs indicating involvement of central nervous system, peripheral nervous system, to non-neurological manifestations [ 5 , 6 ].…”

“…This patient was hypertonic and he often had painful spasms while walking due to a significant increase in muscle tone in the lower limbs. Actually, muscle tone in juvenile type SD patients could be both increased [ 8 ] or decreased [ 6 ], and dystonia could be seen in some juvenile SD patients (Table 2 ). This patient had pyramidal signs, exaggerated tendon reflexes, and ankle clonus.…”

“…Indeed, pyramidal signs and increased tendon reflex were only present in a part of juvenile SD patients (Table 2 ). Individuals with motor neuron disease phenotype of SD had brisk or exaggerated tendon reflexes especially in adults [ 6 , 7 ]. Those signs indicated upper motor neuron involvement in this patient.…”

“…Those signs indicated upper motor neuron involvement in this patient. Epilepsy could be seen in juvenile SD as well, although it is less common compared to infantile SD [ 6 ]. However, epilepsy was not found in this patient.…”

“…The most common subtype is infantile SD with onset age before 9 months old. The onset age range of juvenile SD is controversial, which can be between 2 and 10 years old [ 6 ] or between 1 and 18 years old [ 5 ]. In contrast to the most prevalent infantile SD, the juvenile SD is rarely reported.…”