Genetic panel for the Bull Terrier that groups three molecular tests for hereditary diseases described in the breed: hereditary laryngeal paralysis (LP), lethal acrodermatitis (LAD) and primary lens luxation (PLL). Each condition has a distinct molecular basis and its own inheritance pattern. The panel makes it possible to identify carriers and plan matings while minimising the appearance of affected animals; it does not replace ocular examination or clinical respiratory assessment.

Applicable breed: Bull Terrier (also Miniature Bull Terrier for PLL). Carrier frequencies in the breeding population are not reliably published (limited data).

- Inspiratory stridor and exertional dyspnoea (LP)
- Voice changes (altered bark) and exercise intolerance
- Papular and crusted dermatitis on distal areas from puppyhood (LAD)
- Diarrhoea, failure to thrive, recurrent pneumonia and early death (LAD)
- Altered vision, painful red eye and mydriasis (acute PLL)
- Lens luxation with secondary glaucoma and blindness (PLL)

Lethal acrodermatitis (LAD) in the Bull Terrier was characterised as a recessive entity in puppies with chronic papulopustular dermatosis, diarrhoea and recurrent pneumonia, and its molecular basis was identified in 2018: Bauer et al. found a splicing variant in MKLN1 (c.400+3A>C) that causes skipping of exon 4. Primary lens luxation (PLL) was linked to ADAMTS17: Farias et al. (2010) identified the donor site mutation of intron 10 (c.1473+1G>A) and Gould et al. (2011) demonstrated its wide distribution across breeds. Laryngeal paralysis (LP) in the Bull Terrier has a multifactorial basis: Hadji Rasouliha et al. (2019) described a 36-bp insertion in RAPGEF6 (c.1793_1794ins36) as a major risk factor.

- Genotype breeding animals before mating; the panel covers three conditions in a single sample
- For LAD (recessive): do not mate two carriers — 25% risk of affected homozygotes with early death; carrier×clear is safe for offspring intended for breeding if tested
- For PLL (autosomal recessive): do not mate two carriers; prioritise clear animals for breeding and perform annual ophthalmological assessment
- For LP: the RAPGEF6 variant is a major risk factor in a multifactorial trait; avoid mating affected animals and keep a genealogical record of lines with cases
- After a confirmed clinical case, do not repeat the parental mating and communicate the status to the buyer

LP must be differentiated from idiopathic laryngeal paralysis of the elderly and from secondary forms (neurological, traumatic, hypothyroidism). LAD has a differential diagnosis with juvenile demodicosis, juvenile pemphigoid and dermatophytosis; biopsy and the molecular test confirm it. PLL must be differentiated from traumatic luxation or luxation secondary to uveitis/glaucoma. Annual ocular examination (ECVO/CERF) in all breeding animals.

1. Bauer A et al. 2018. MKLN1 splicing defect in dogs with lethal acrodermatitis. PLoS Genet. PMID: 29565995. 2. Farias FH et al. 2010. An ADAMTS17 splice donor site mutation in dogs with primary lens luxation. Invest Ophthalmol Vis Sci. PMID: 20375329. 3. Gould D et al. 2011. ADAMTS17 mutation associated with primary lens luxation is widespread among breeds. Vet Ophthalmol. PMID: 22050825. 4. Hadji Rasouliha S et al. 2019. A RAPGEF6 variant constitutes a major risk factor for laryngeal paralysis in dogs. PLoS Genet. PMID: 31647804. OMIA:002146-9615, OMIA:000588-9615, OMIA:002222-9615.