MONDO:0010100 Tay-Sachs disease remains a separate sibling branch.
MONDO child terms exist for Sandhoff disease, infantile / juvenile / adult forms.
ClinGen checks
ClinGen validity row maps HEXB to Sandhoff disease (MONDO:0010006).
ClinGen mode of inheritance is autosomal recessive.
ClinGen classification is Definitive.
Evidence coverage checks
Human Sandhoff abstracts used for inheritance, HEXB framing, and phenotype anchors.
Model-organism abstracts used for lysosomal dysfunction, gliosis, ER stress, and therapy nodes.
GM2-branch reviews / natural history were kept only where the abstract language applied to Sandhoff explicitly or stated no Tay Sachs versus Sandhoff difference.