In other species: dog , domestic cat , horse , llama , alpaca

Categories: Vision / eye phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 149700 (trait)

Mendelian trait/disorder: unknown

Considered a defect: yes

Cross-species summary: Acquired or congenital blocked tear duct, also called dacryostenosis 

Species-specific name: Also known as nasolacrimal duct fistula or lacrimal fistula.

Species-specific description: Previously listed in OMIA as OMIA:001693-9913 : Lacrimal fistula in Bos taurus (taurine cattle) [06.05.2024]

Inheritance:  With the incidence of this disorder differing substantially in the offspring of three Brown Swiss bulls, Braun et al. (2014) suggested "a hereditary cause of nasolacrimal duct fistula in Brown Swiss cattle". 

Clinical features:  From a survey of 265 Brown Swiss cattle, Braun et al. (2014) reported: "The fistulae were located medial to the medial canthus of the eye and were 1 to 10 mm (median, 1 mm) in height and 1 to 12 mm (median, 2 mm) in length. The shape of the opening was circular in 58, oval in 23 and slit-like in three. One other animal had a large opening with an atypical shape and another had an abnormal medial canthus with several fistulous openings. Seventy openings were pigmented and 52 were hairless. The fistulae were clinically significant in 12 animals." 

Prevalence: As reported by Braun et al. (2014): "Of 265 [Brown Swiss] cattle examined, 54 had unilateral (n = 24) or bilateral fistula (n = 30)." 

Breeds: Brown Swiss (Cattle) (VBO_0000166), Holstein Friesian (Cattle) (VBO_0000239).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).