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UniProtKB/Swiss-Prot P08174: Variant p.Ser199Leu

Complement decay-accelerating factor
Gene: CD55
Variant information

Variant position:  199
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 Serine (S) to Leucine (L) at position 199 (S199L, p.Ser199Leu).
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 small size and polar (S) to medium size and hydrophobic (L)
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

Polymorphism:  Responsible for the Cromer blood group system (CROM) [MIM:613793]. It consists of at least 8 high-incidence (Cr(a), Tc(a), Dr(a), Es(a), WES(b), UMC, IFC and GUTI) and three low-incidence (Tc(b), Tc(c) and WES(a)) antigens that reside on DAF. In the Cromer phenotypes Dr(a-) and Inab there is reduced or absent expression of DAF, respectively. In the case of the Dr(a-) phenotype, a single nucleotide substitution within exon 5 accounts for two changes: a simple amino acid substitution, Leu-199 that is the basis of the antigenic variation, and an alternative splicing event that underlies the decreased expression of DAF in this phenotype. The Inab phenotype is a very rare one in which the red blood cells lack all Cromer system antigens. The red blood cells of individuals with Inab phenotype have a deficiency of DAF, but these individuals are not known to have any associated hematologic or other abnormalities (PubMed:12675719).
Additional information on the polymorphism described.

Variant description:  In Dr(a-) antigen.
Any additional useful information about the variant.

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



Sequence information

Variant position:  199
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  381
The length of the canonical sequence.

Location on the sequence:   GILFGATISFSCNTGYKLFG  S TSSFCLISGSSVQWSDPLPE
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.

TypePositionsDescription
Chain 35 – 353 Complement decay-accelerating factor
Domain 161 – 222 Sushi 3
Disulfide bond 163 – 204
Disulfide bond 190 – 220


Literature citations

Molecular basis of reduced or absent expression of decay-accelerating factor in Cromer blood group phenotypes.
Lublin D.M.; Mallinson G.; Poole J.; Reid M.E.; Thompson E.S.; Ferdman B.R.; Telen M.J.; Anstee D.J.; Tanner M.J.A.;
Blood 84:1276-1282(1994)
Cited for: VARIANT BLOOD GROUP DR(A-) LEU-199;

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.