OMIA:002554-9685 : Osteochondromatosis, EXT1-related in Felis catus (domestic cat)

Categories: Skeleton phene (incl. short stature & teeth)

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 133700 (trait) , 608177 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal dominant

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2022

History: Fujii et al. (2022) were the first to show "that genetic variants can have etiologic roles in osteochondromatosis in cats, as in humans and other animals".

Molecular basis: Fujii et al. (2022) "examined the EXT1 and EXT2 [comparative candidate] genes in a feline leukemia virus-negative cat with osteochondromatosis. Genetic analysis revealed a heterozygous single base pair duplication in exon 6 of the EXT1 gene (XM_023248762.2:c.1468dupC), leading to a premature stop codon in the EXT1 protein. Notably, this frameshift variant is recognized as one of the most common pathogenic variants in human osteochondromatosis."

Clinical features: Fujii et al. (2022): "A 1- year- old, mixed- breed, indoor- only, neutered male cat was presented with non-inf lammatory masses in multiple bones. Computed tomography revealed pro-liferative lesions in the right ulna, left humerus, right scapula, pubis and ischium".

Pathology: Fujii et al. (2022): "Histopathological examination revealed that bone and cartilage tissues (right ulna and right scapula) collected via biopsy needle did not show malignancy. FeLV antigen and feline immunodeficiency virus (FIV) antibody were absent as per the immunochromatographic test kit (One Step FIV Antibody, FeLV Antigen Test, Kyokuto Pharmaceutical Industrial Co.). In addition, FeLV proviral DNA was not detected in real-time PCR of cat whole blood conducted in IDEXX laboratories. Based on the above findings, we diagnosed this case as FeLV-negative OC."

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
EXT1 exostosin glycosyltransferase 1 Felis catus F2 NC_058385.1 (62141215..61852911) EXT1 Homologene, Ensembl , NCBI gene


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WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
1467 Osteochondromatosis (feline leukemia virus-negative) EXT1 duplication Naturally occurring variant F.catus_Fca126_mat1.0 F2 g.61870704dup c.1468dup p.(L490Pfs*31) XM_023248762.2; 2022 35719100

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2023). OMIA:002554-9685: Online Mendelian Inheritance in Animals (OMIA) [dataset].


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

2023 Gómez, Á., Rodríguez-Largo, A., Pérez, E., Calvo-Sánchez, N., Loomans, S., Chiers, K., Monteagudo, L., Luján, L., Pérez, M. :
Feline osteochondromatosis in a 12-year-old feline leukaemia virus-negative cat. J Comp Pathol 205:24-26, 2023. Pubmed reference: 37597496. DOI: 10.1016/j.jcpa.2023.07.003.
2022 Fujii, Y., Uno, A., Takitani, S., Iwasaki, R., Yoshikawa, R., Okajima, M., Makino, Y., Ito, N., Mori, T. :
A frameshift variant in the EXT1 gene in a feline leukemia virus-negative cat with osteochondromatosis. Anim Genet , 2022. Pubmed reference: 35719100. DOI: 10.1111/age.13232.

Edit History

  • Created by Frank Nicholas on 28 Jun 2022
  • Changed by Frank Nicholas on 28 Jun 2022
  • Changed by Imke Tammen2 on 10 Nov 2023