title: Adult Sandhoff disease with 2 mutations in the HEXB gene presenting as brachial amyotrophic diplegia.
abstract: Sandhoff disease is a rare autosomal recessive metabolic disorder of GM2 gangliosides. It is caused by a lack of functional N-acetyl-β-D-glucosaminidase A and B because of mutations in the HEXB gene. We describe a 55-year-old woman with adult Sandhoff disease presenting as brachial amyotrophic diplegia. The assay of total hexosaminidase involving A and B showed decreased level of these activities. Hex-A was 4.6 nmol·min·mL (normal: 7.0-20.0 nmol·min·mL) and Hex-B was 0.1 nmol·min·mL (normal: 1.0-10.0 nmol·min·mL), respectively. Analysis of HEXB gene demonstrated 2 point mutations that were located at the exon 5 (c.619A>G) and exon 11 (c.1250C>T). Compound heterozygosity of these 2 mutations may trigger the development of distinct adult Sandhoff disease phenotype. Sandhoff disease should be considered in the differential diagnosis of lower motor neuron disease, such as brachial amyotrophic diplegia, even if the age at onset is more than 50 years.
authors.affiliation: Department of Neurology, College of Medicine, Jeju National University, Jeju, Korea.
authors.forename: Sa-Yoon
authors.initials: SY
authors.lastname: Kang
authors.forename: Sook Keun
authors.initials: SK
authors.lastname: Song
authors.forename: Jung Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: Jay Chol
authors.initials: JC
authors.lastname: Choi
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Kang
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000175:diagnosis* / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D012497:Sandhoff Disease / Q000175:diagnosis* / Q000235:genetics; D054821:beta-Hexosaminidase beta Chain / Q000235:genetics*
chemical_list: C513386:HEXB protein, human; D054821:beta-Hexosaminidase beta Chain