Multidisease genetic panel for the Pug that brings together four molecular tests: pyruvate kinase deficiency (PK), primary lens luxation (PLL), necrotizing meningoencephalitis / small dog disease (NME/PDE) and degenerative myelopathy (DM exon 2). Each condition has its own molecular basis and inheritance. The panel is complementary to hematological, ophthalmological and neurological follow-up in breeding selection.

Applicable breed: Pug. The PKLR and ADAMTS17 variants have no published frequencies in the breed; the frequency of the risk haplotype for NME/PDE is high in the breed, but the clinical disease has a low incidence. Reliable carrier frequencies in the breeding population are not published systematically (limited data).

- Chronic hemolytic anemia with pale mucous membranes, lethargy and splenomegaly (PK)
- Hyperthermia episodes during anesthesia or stress with muscle rigidity (MH)
- Painful red eye, mydriasis and altered vision (acute PLL)
- Lens luxation with secondary glaucoma (PLL)
- Progressive neurological alterations: seizures, behavioral change, ataxia (NME/PDE)
- Progressive paresis of the hind limbs with proprioceptive ataxia (DM)

Canine pyruvate kinase deficiency was associated with the PKLR gene in the Basenji and has been described in other breeds, including the Pug. PLL was associated with ADAMTS17 in terriers and small breeds. Necrotizing meningoencephalitis of the Pug (PDE/NME) is multifactorial: risk loci have been described in the canine leukocyte antigen (DLA) region, but there is no single Mendelian test. Canine DM was linked to the exon 2 variant of SOD1 in 2009; in the Pug, homozygotes are at elevated risk, but the clinical presentation may overlap with Pug myelopathy (Pug dog encephalitis and other neurological conditions).

- Genotype breeding animals before mating; the panel covers four conditions in a single sample
- For PK (recessive): do not mate two carriers — 25% risk of affected homozygotes; carrier×clear is safe for offspring intended for breeding if tested
- For PLL (dominant): heterozygotes transmit the variant to 50% of the offspring; prioritize clear animals for breeding
- For NME/PDE: the absence of the risk haplotype does not guarantee protection; avoid mating two animals with a high-risk haplotype
- For DM: do not breed homozygotes; also assess back conformation so as not to confuse with confluent myelopathy
- After a confirmed clinical case, do not repeat the parental mating and communicate the status to the buyer

PLL must be differentiated from traumatic luxation or luxation secondary to uveitis. NME/PDE is a diagnosis of exclusion with MRI and CSF; the risk haplotype does not confirm the disease. DM in the Pug is controversial: SOD1 homozygotes may have conditions overlapping with confluent myelopathy, hemivertebrae and other malformations — always rule out spinal cord compression before attributing the condition to SOD1.

1. Gultekin GI et al. 2012, mutaciones de piruvato quinasa eritrocítica en perros (PMID 22805166)
3. ADAMTS17 y luxación primaria de lente: mutación extendida entre razas (PMID 22050825); frecuencia del alelo (PMID 34870369)
4. Greer KA et al. 2010, meningoencefalitis necrotizante del Carlino asociada a DLA clase II (PMID 20403140)
5. Awano T et al. 2009, SOD1 exón 2 y mielopatía degenerativa (PMID 19188595)