title: [Clinical and molecular characteristics of a child with juvenile Sandhoff disease].
abstract: OBJECTIVE
  To explore the clinical features and molecular mutation of HEXB gene in a case with juvenile Sandhoff disease.
  
  
  METHODS
  We retrospectively reviewed the clinical, neuroimaging and biochemical findings in this Chinese child with juvenile Sandhoff disease. Hexosaminidase A and hexosaminidase A & B activities were measured in blood leukocytes by fluorometric assay. HEXB gene molecular analysis was performed by PCR and direct sequencing.
  
  
  RESULTS
  The 9-year-old boy was admitted for psychomotor regression. He presented slowly progressive gait disorder and dysarthria during the last three years. Cranial MRI revealed a marked cerebellar atrophy with normal intensity in the thalamus and basal ganglia. Brain MRS showed normal in the thalamus and basal ganglia. Hexosaminidase A was 69.5 (mg·h) [normal controls 150-360 nmol/(mg·h)], hexosaminidase A & B activity was 119 nmol/(mg·h)[normal controls 600-3 500 nmol/(mg·h)], confirming the diagnosis of Sandhoff disease. The patient was a compound heterozygote for a novel deletion mutation c.1404delT (p. P468P fsX62) and a reported mutation c.1509-26G>A.
  
  
  CONCLUSIONS
  The clinical features of juvenile Sandhoff disease include ataxia, dysarthria and cerebellar atrophy. The enzyme assay and molecular analysis of HEXB gene can confirm the diagnosis of Sandhoff disease. The novel mutation c.1404delT(p. P468P fsX62) is a disease-related mutation.
authors.affiliation: Department of Endocrinology and Metabolism, Guangzhou Women and Children's Medical Center, Guangzhou 510623, China.
authors.forename: Yonglan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Endocrinology and Metabolism, Guangzhou Women and Children's Medical Center, Guangzhou 510623, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Xie
authors.affiliation: Department of Endocrinology and Metabolism, Guangzhou Women and Children's Medical Center, Guangzhou 510623, China.
authors.forename: Jipeng
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Endocrinology and Metabolism, Guangzhou Women and Children's Medical Center, Guangzhou 510623, China.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Endocrinology and Metabolism, Guangzhou Women and Children's Medical Center, Guangzhou 510623, China.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Endocrinology and Metabolism, Guangzhou Women and Children's Medical Center, Guangzhou 510623, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002524:Cerebellar Ataxia / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics; D002648:Child; D004252:DNA Mutational Analysis; D006579:Heterozygote; D054818:Hexosaminidase A / Q000097:blood / Q000378:metabolism; D054819:Hexosaminidase B / Q000097:blood / Q000378:metabolism; D006801:Humans; D007962:Leukocytes / Q000201:enzymology; D008279:Magnetic Resonance Imaging; D008297:Male; D009154:Mutation; D011859:Radiography; D012189:Retrospective Studies; D012497:Sandhoff Disease / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics*; D054821:beta-Hexosaminidase beta Chain / Q000235:genetics*
chemical_list: C513386:HEXB protein, human; D054818:Hexosaminidase A; D054819:Hexosaminidase B; D054821:beta-Hexosaminidase beta Chain