Biomaterial Database

A shortened beta-hexosaminidase alpha-chain in an Italian patient with infantile Tay-Sachs disease. 1987

G Zokaeem, and J Bayleran, and P Kaplan, and P Hechtman, and E F Neufeld

Fibroblasts derived from a beta-hexosaminidase A (HexA)-deficient infant with clinically classic Tay-Sachs disease synthesized a precursor alpha-chain that was smaller than its normal counterpart. Fibroblasts from the infant's parents, who were consanguinous, produced both normal and mutant alpha-chains. The size difference, estimated to be 2-3 kilodaltons on the basis of sodium dodecyl sulfate-polyacrylamide-gel electrophoresis, persisted after removal of oligosaccharides with endo-H and is therefore attributable to a shortened polypeptide. The mutant alpha-chain did not undergo the further posttranslational modifications characteristic of its normal counterpart--i.e., synthesis of the mannose phosphate recognition marker, association with the beta-chain to give HexA, and proteolytic conversion to the mature form. Nor was it secreted, even in the presence of NH4Cl. Instead, it disappeared in the course of a 20-h chase. These results suggest that the mutant alpha-chain was trapped in an early biosynthetic compartment, either the endoplasmic reticulum or the cis-Golgi. The mutation appears to be different from all those previously described in patients with clinically classic Tay-Sachs disease.

UI	MeSH Term	Description	Entries
D007223	Infant	A child between 1 and 23 months of age.	Infants
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D005260	Female		Females
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D005819	Genetic Markers	A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.	Chromosome Markers,DNA Markers,Markers, DNA,Markers, Genetic,Genetic Marker,Marker, Genetic,Chromosome Marker,DNA Marker,Marker, Chromosome,Marker, DNA,Markers, Chromosome
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001619	beta-N-Acetylhexosaminidases	A hexosaminidase specific for non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. It acts on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES. Two specific mammalian isoenzymes of beta-N-acetylhexoaminidase are referred to as HEXOSAMINIDASE A and HEXOSAMINIDASE B. Deficiency of the type A isoenzyme causes TAY-SACHS DISEASE, while deficiency of both A and B isozymes causes SANDHOFF DISEASE. The enzyme has also been used as a tumor marker to distinguish between malignant and benign disease.	beta-N-Acetylhexosaminidase,N-Acetyl-beta-D-hexosaminidase,beta-Hexosaminidase,beta-N-Acetyl-D-hexosaminidase,beta-N-Acetyl-hexosaminidase,N Acetyl beta D hexosaminidase,beta Hexosaminidase,beta N Acetyl D hexosaminidase,beta N Acetyl hexosaminidase,beta N Acetylhexosaminidase,beta N Acetylhexosaminidases
D013661	Tay-Sachs Disease	An autosomal recessive neurodegenerative disorder characterized by the onset in infancy of an exaggerated startle response, followed by paralysis, dementia, and blindness. It is caused by mutation in the alpha subunit of the HEXOSAMINIDASE A resulting in lipid-laden ganglion cells. It is also known as the B variant (with increased HEXOSAMINIDASE B but absence of hexosaminidase A) and is strongly associated with Ashkenazic Jewish ancestry.	G(M2) Gangliosidosis, Type I,Gangliosidosis G(M2), Type I,Gangliosidosis GM2, B Variant,Hexosaminidase A Deficiency Disease,Tay-Sachs Disease, B Variant,Amaurotic Familial Idiocy,B Variant GM2 Gangliosidosis,B Variant GM2-Gangliosidosis,Deficiency Disease Hexosaminidase A,Familial Amaurotic Idiocy,GM2 Gangliosidosis, B Variant,GM2 Gangliosidosis, Type 1,GM2 Gangliosidosis, Type I,GM2-Gangliosidosis, Type I,Gangliosidosis GM2 , Type 1,Gangliosidosis GM2, Type I,HexA Deficiency,Hexosaminidase A Deficiency,Hexosaminidase alpha-Subunit Deficiency (Variant B),Sphingolipidosis, Tay-Sachs,Amaurotic Idiocy, Familial,B Variant GM2-Gangliosidoses,Deficiency, Hexosaminidase A,Deficiency, Hexosaminidase alpha-Subunit (Variant B),GM2-Gangliosidosis, B Variant,Hexosaminidase alpha Subunit Deficiency (Variant B),Sphingolipidosis, Tay Sachs,Tay Sachs Disease,Tay Sachs Disease, B Variant,Tay-Sachs Sphingolipidosis,Type I GM2-Gangliosidosis
D054818	Hexosaminidase A	A mammalian beta-hexosaminidase isoform that is a heteromeric protein comprized of both hexosaminidase alpha and hexosaminidase beta subunits. Deficiency of hexosaminidase A due to mutations in the gene encoding the hexosaminidase alpha subunit is a case of TAY-SACHS DISEASE. Deficiency of hexosaminidase A and HEXOSAMINIDASE B due to mutations in the gene encoding the hexosaminidase beta subunit is a case of SANDHOFF DISEASE.	Hex A,beta-N-Acetylhexosaminidase A,beta N Acetylhexosaminidase A