UniProtKB/Swiss-Prot P06865: Variant p.Trp474Cys

Beta-hexosaminidase subunit alpha
Gene: HEXA
Chromosomal location: 15q23-q24
Variant information

Variant position:  474
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants have been found in patients and disease-association is reported in literature. However, this classification is not a definitive assessment of variant pathogenicity.
  • Polymorphism: No disease-association has been reported.
  • Unclassified: Variants have been found in patients but disease-association remains unclear.

Residue change:  From Tryptophan (W) to Cysteine (C) at position 474 (W474C, p.Trp474Cys).
Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.

Physico-chemical properties:  Change from large size and aromatic (W) to medium size and polar (C)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -2
The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Involvement in disease:  GM2-gangliosidosis 1 (GM2G1) [MIM:272800]: An autosomal recessive lysosomal storage disease marked by the accumulation of GM2 gangliosides in the neuronal cells. It is characterized by GM2 gangliosides accumulation in the absence of HEXA activity, leading to neurodegeneration and, in the infantile form, death in early childhood. It exists in several forms: infantile (most common and most severe), juvenile and adult (late-onset). {ECO:0000269|PubMed:1301189, ECO:0000269|PubMed:1301190, ECO:0000269|PubMed:1302612, ECO:0000269|PubMed:14566483, ECO:0000269|PubMed:1532289, ECO:0000269|PubMed:1837283, ECO:0000269|PubMed:2144098, ECO:0000269|PubMed:2522679, ECO:0000269|PubMed:2970528, ECO:0000269|PubMed:7717398, ECO:0000269|PubMed:7837766, ECO:0000269|PubMed:7898712, ECO:0000269|PubMed:7951261, ECO:0000269|PubMed:8445615, ECO:0000269|PubMed:8490625, ECO:0000269|PubMed:8581357, ECO:0000269|PubMed:8757036, ECO:0000269|PubMed:9150157, ECO:0000269|PubMed:9338583, ECO:0000269|PubMed:9375850, ECO:0000269|PubMed:9401008, ECO:0000269|PubMed:9603435}. Note=The disease is caused by mutations affecting the gene represented in this entry.
The name and a short description of the disease associated with the variant. For more information about the disease, the user can refer to OMIM, following the link provided after the disease acronym.

Variant description:  In GM2G1; subacute.
Any additional useful information about the variant.

Sequence information

Variant position:  474
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  529
The length of the canonical sequence.

The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.

Sequence annotation in neighborhood:  
The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.

Chain 89 – 529 Beta-hexosaminidase subunit alpha
Alternative sequence 361 – 529 Missing. In isoform 2.

Literature citations

W474C amino acid substitution affects early processing of the alpha-subunit of beta-hexosaminidase A and is associated with subacute G(M2) gangliosidosis.
Petroulakis E.; Cao Z.; Clarke J.T.R.; Mahuran D.J.; Lee G.; Triggs-Raine B.;
Hum. Mutat. 11:432-442(1998)
Cited for: VARIANT GM2G1 CYS-474;

Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.