HEXB (Hexosaminidase B subunit beta) is the beta subunit of the lysosomal enzyme beta-hexosaminidase that catalyzes the degradation of the ganglioside GM2 and other molecules containing terminal N-acetyl hexosamines. Mutations in the alpha or beta subunit genes of beta-hexosaminidase lead to an accumulation of GM2 ganglioside in neurons and neurodegenerative disorders termed the GM2 gangliosidoses. Beta subunit gene mutations lead to Sandhoff disease (GM2-gangliosidosis type II), a lysosomal disorder characterized by progressive neurodegeneration and childhood mortality. In immunohistochemistry of normal tissue, HEXB has cytoplasmic positivity in the lung, epididymis, testes, prostate, heart muscle, some immune tissues, gastrointestinal tissues, endocrine tissues, the kidney, the pancreas and the brain. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804; PLoS One. 2012; 7(7): e41516, PMID: 22848519;