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UniProtKB/Swiss-Prot P07359: Variant p.Thr161Met

Platelet glycoprotein Ib alpha chain
Gene: GP1BA
Variant information

Variant position:  161
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  LB/B
The variants are classified into three categories: LP/P, LB/B and US.
  • LP/P: likely pathogenic or pathogenic.
  • LB/B: likely benign or benign.
  • US: uncertain significance

Residue change:  From Threonine (T) to Methionine (M) at position 161 (T161M, p.Thr161Met).
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 medium size and polar (T) to medium size and hydrophobic (M)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -1
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

Polymorphism:  Position 161 is associated with platelet-specific alloantigen Siba (PubMed:1586750). Siba(-) has Thr-161 and Siba(+) has Met-161 (PubMed:1586750). Siba is involved in neonatal alloimmune thrombocytopenia (NATP) (PubMed:1586750, PubMed:7632942).Polymorphisms arise from a variable number of tandem 13-amino acid repeats of S-E-P-A-P-S-P-T-T-P-E-P-T in the mucin-like macroglycopeptide (Pro/Thr-rich) domain (PubMed:1577776, PubMed:7632942). Allele D contains one repeat starting at position 415, allele C contains two repeats, allele B (shown here) contains three repeats and allele A contains four repeats (PubMed:1577776). Allele B is associated with susceptibility to nonarteritic anterior ischemic optic neuropathy (PubMed:1577776). -
Additional information on the polymorphism described.

Variant description:  In Siba(+).
Any additional useful information about the variant.

Other resources:  
Links to websites of interest for the variant.

Sequence information

Variant position:  161
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  652
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.

Residue conservation: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.




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 17 – 652 Platelet glycoprotein Ib alpha chain
Chain 17 – 506 Glycocalicin
Topological domain 17 – 531 Extracellular
Repeat 141 – 162 LRR 5
Glycosylation 175 – 175 N-linked (GlcNAc...) asparagine
Turn 157 – 162

Literature citations

SeattleSNPs variation discovery resource;

Genetic and structural characterization of an amino acid dimorphism in glycoprotein Ib alpha involved in platelet transfusion refractoriness.
Murata M.; Furihata K.; Ishida F.; Russell S.R.; Ware J.; Ruggeri Z.M.;
Blood 79:3086-3090(1992)

The largest variant of platelet glycoprotein Ib alpha has four tandem repeats of 13 amino acids in the macroglycopeptide region and a genetic linkage with methionine145.
Ishida F.; Furihata K.; Ishida K.; Yan J.; Kitano K.; Kiyosawa K.; Furuta S.;
Blood 86:1357-1360(1995)

Characterization of single-nucleotide polymorphisms in coding regions of human genes.
Cargill M.; Altshuler D.; Ireland J.; Sklar P.; Ardlie K.; Patil N.; Shaw N.; Lane C.R.; Lim E.P.; Kalyanaraman N.; Nemesh J.; Ziaugra L.; Friedland L.; Rolfe A.; Warrington J.; Lipshutz R.; Daley G.Q.; Lander E.S.;
Nat. Genet. 22:231-238(1999)
Cited for: VARIANTS HIS-72 AND MET-161;

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.