Characterization of the mutant β-subunit of β-hexosaminidase for dimer formation responsible for the adult form of Sandhoff disease with the motor neuron disease phenotype.
These results provide additional insight into juvenile-onset G(M2)-gangliosidoses and further expand the number of β-hexosaminidase mutations associated with motor neuron disease.
However, we have earlier demonstrated the presence of partial beta-Hex A (30-50% of normal) even in the absence of beta-Hex B in an adult with motor neuron disease.
The phenotypic expression of this disease is similar to motor neuron disease due to alpha locus mutations, which suggests that the Hex A deficiency, even though only a partial one, may be the important pathogenic factor.