CMAH R310P - GET-Evidence

Note: This variant has not been sufficiently evaluated by a GET-Evidence editor.

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(CMAH Arg310Pro)

Short summary

This is a pseudogene; variants are of no consequence.

Variant evidence
Computational -
Functional -
Case/Control -
Familial -
Clinical importance
Severity -
Treatability -
Penetrance -


Insufficiently evaluated not reviewed

(The "insufficiently evaluated" qualifier is assigned automatically based on the above evidence and importance scores.)

Inheritance pattern


Summary of published research, and additional commentary


Allele frequency

  • G @ chr6:25205276: 7.8% (10/128) in GET-Evidence
  • Frequency shown in summary reports: 7.8% (10/128)


Irie A, Koyama S, Kozutsumi Y, Kawasaki T, Suzuki A. The molecular basis for the absence of N-glycolylneuraminic acid in humans. J Biol Chem. 1998 Jun 19;273(25):15866-71. PubMed PMID: 9624188.

N-Glycolylneuraminic acid (NeuGc) is abundantly expressed in most mammals, but it is not detectable in humans. The expression of NeuGc is controlled by cytidine monophospho-N-acetylneuraminic acid (CMP-NeuAc) hydroxylase activity. We previously cloned a cDNA for mouse CMP-NeuAc hydroxylase and found that the human genome contains a homologue. We report here the molecular basis for the absence of NeuGc in humans. We cloned a cDNA for human CMP-NeuAc hydroxylase from a HeLa cell cDNA library. The cDNA encodes a 486-amino acid protein, and its deduced amino acid sequence lacks a domain corresponding to the N-terminal 104 amino acids of the mouse CMP-NeuAc hydroxylase protein, although the human protein is highly identical (93%) to the rest of the mouse hydroxylase protein. The N-terminal truncation of the human hydroxylase is caused by deletion of a 92-base pair-long exon in human genomic DNA. The human hydroxylase expressed in COS-7 cells exhibited no enzymatic activity, and a mouse hydroxylase mutant, which lacks the N-terminal domain, was also inactive. A chimera composed of the human hydroxylase and the N-terminal domain of the mouse hydroxylase displayed the enzyme activity. These results indicate that the human homologue of CMP-NeuAc hydroxylase is inactive because it lacks an N-terminal domain that is essential for enzyme activity. The absence of NeuGc in human glycoconjugates is due to a partial deletion in the gene that encodes CMP-NeuAc hydroxylase.








hu604D39 - CGI sample GS00253-DNA_B02_200_37
het G @ chr6:25097298




huAE6220 - CGI sample GS00253-DNA_H01_200_37
het G @ chr6:25097298


GS06985 - var-GS06985-1100-36-ASM
het G @ chr6:25205277


GS18502 - var-GS18502-1100-36-ASM
het G @ chr6:25205277


GS18505 - var-GS18505-1100-36-ASM
het G @ chr6:25205277


GS18508 - var-GS18508-1100-36-ASM
het G @ chr6:25205277


GS19669 - var-GS19669-1100-36-ASM
het G @ chr6:25205277


GS19670 - var-GS19670-1100-36-ASM
het G @ chr6:25205277


GS19700 - var-GS19700-1100-36-ASM
het G @ chr6:25205277


Other external references

  • rs1128827

Other in silico analyses

  • NBLOSUM100 score = 5
  • GET-Evidence autoscore = 0

Edit history

Gene search

"GENE" or "GENE A123C":

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