UniProtKB/Swiss-Prot O14746: Variant p.Lys902Asn

Telomerase reverse transcriptase
Gene: TERT
Chromosomal location: 5p15.33
Variant information

Variant position:  902
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 Lysine (K) to Asparagine (N) at position 902 (K902N, p.Lys902Asn).
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 basic (K) to medium size and polar (N)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  0
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:  Dyskeratosis congenita, autosomal dominant, 2 (DKCA2) [MIM:613989]: A rare multisystem disorder caused by defective telomere maintenance. It is characterized by progressive bone marrow failure, and the clinical triad of reticulated skin hyperpigmentation, nail dystrophy, and mucosal leukoplakia. Common but variable features include premature graying, aplastic anemia, low platelets, osteoporosis, pulmonary fibrosis, and liver fibrosis among others. Early mortality is often associated with bone marrow failure, infections, fatal pulmonary complications, or malignancy. 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 DKCA2; abolishes telomerase catalytic activity but no effect on binding to TERC.
Any additional useful information about the variant.



Sequence information

Variant position:  902
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  1132
The length of the canonical sequence.

Location on the sequence:   TFLRTLVRGVPEYGCVVNLR  K TVVNFPVEDEALGGTAFVQM
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.

Human                         TFLRTLVRGVPEYGCVVNLRKTVVNFPVEDEALGGTAFVQM

Mouse                         TFLSTLVHGVPEYGCMINLQKTVVNFPVEPGTLGGAAPYQL

Rat                           AFLSTLVHGVPEYGCMINLQKTVVNFPVETGALGGAAPHQL

Bovine                        DFLRTLVRGVPEYGCQVNLRKTVVNFPVEPGALGGAAPLQL

Dog                           AFLRTLVKGVPEYGCRANLQKTAVNFPVEDGALGSAAPLQL

Baker's yeast                 NIKKLAMGGFQKYNAKANRDKIL------------AVSSQS

Fission yeast                 KFLNLSLRGFEKHNFSTSLEKTVINFENSNGIINNTFFNES

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 1 – 1132 Telomerase reverse transcriptase
Domain 605 – 935 Reverse transcriptase
Alternative sequence 808 – 1132 Missing. In isoform 2 and isoform 4.
Alternative sequence 885 – 947 Missing. In isoform 3.


Literature citations

Haploinsufficiency of telomerase reverse transcriptase leads to anticipation in autosomal dominant dyskeratosis congenita.
Armanios M.; Chen J.-L.; Chang Y.-P.C.; Brodsky R.A.; Hawkins A.; Griffin C.A.; Eshleman J.R.; Cohen A.R.; Chakravarti A.; Hamosh A.; Greider C.W.;
Proc. Natl. Acad. Sci. U.S.A. 102:15960-15964(2005)
Cited for: VARIANT DKCA2 ASN-902; CHARACTERIZATION OF VARIANT DKCA2 ASN-902;

Functional characterization of natural telomerase mutations found in patients with hematologic disorders.
Xin Z.T.; Beauchamp A.D.; Calado R.T.; Bradford J.W.; Regal J.A.; Shenoy A.; Liang Y.; Lansdorp P.M.; Young N.S.; Ly H.;
Blood 109:524-532(2007)
Cited for: VARIANT AA SUSCEPTIBILITY ASN-570; CHARACTERIZATION OF VARIANTS ASN-570; ASP-682; ARG-721; MET-726; ASN-902; TRP-979 AND LEU-1127;

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.