Categories: Integument (skin) phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 113811 (gene) , 619787 (trait)

Links to relevant human diseases in MONDO:

• MONDO:0030750: epidermolysis bullosa, junctional 4, intermediate

Single-gene trait/disorder: yes

Mode of inheritance: Probably autosomal recessive

Disease-related: yes

Key variant known: yes

Year key variant first reported: 2023

Molecular basis: Kiener et al. (2023) investigated two unrelated cats with epidermolysis bullosa (EB): "Whole genome sequencing of both affected cats revealed independent homozygous variants in COL17A1 encoding the collagen type XVII alpha 1 chain. ... The identified splice site variant in case 1 [American Shorthair], c.3019+1del [omia.variant:1634], was predicted to lead to a complete deficiency in collagen type XVII. Case 2 [European Shorthair] had a splice region variant, c.769+5G>A [omia.variant:1635]. Assessment of the functional impact of this variant on the transcript level demonstrated partial aberrant splicing with residual expression of wildtype transcript."
Fussell et al. (2026) "describe the clinical and morphologic features of JEB [junctional epidermolysis bullosa] in a 4-mo-old domestic shorthair kitten and identify the underlying genetic variant. ... Whole genome sequencing identified a homozygous 2-bp deletion in exon 7 of COL17A1 [omia.variant:1873], predicted to result in loss of function and disrupted binding domains."

Clinical features: Kiener et al. (2023) "investigated two unrelated cats with recurring erosions and ulcers on ear pinnae, oral mucosa, and paw pads that were suggestive of EB. ... Case 1 [American Shorthair] was severe and had to be euthanized at 5 months of age. Case 2 [European Shorthair] had a milder course and was alive at 11 years of age ... ."
Fussell et al. (2026): "The [domestic shorthair] kitten was presented with blistering lesions affecting friction-prone areas of haired skin, mucocutaneous junctions, and oral mucosa."

Pathology: Kiener et al. (2023): "Histopathology confirmed the diagnosis of EB in both cats."
Fussell et al. (2026): "Histopathology revealed extensive subepidermal cleft formation in affected tissues. Periodic acid–Schiff (PAS) staining showed a thin, PAS-positive line along the dermal side of the cleft, consistent with retention of the lamina densa. Transmission electron microscopy confirmed separation at the level of the lamina lucida with intact basal keratinocytes."

Breeds: American Shorthair (Cat) (VBO_0100018), European Shorthair (Cat) (VBO_0100094).
Breeds in which the phene or likely causal variants have been documented. If a likely causal variant has been documented, see variant-specific breed information in the variant table. (Breed information may be incomplete).

Associated gene: