Test Detail

Centronuclear myopathy (CNM) of the Labrador Retriever: congenital myopathy due to an exonic SINE insertion in the PTPLA gene (now HACD1), which alters splicing and produces progressive muscle weakness from the first months of life, with exercise intolerance, abnormal postures and muscle atrophy. It is inherited in an autosomal recessive manner. The test detects the Labrador founder variant; it is complementary to neurological examination and muscle biopsy.

Labrador Retriever worldwide (disseminated founder mutation; Mauri et al. 2012). In an Italian sample the allele frequency was 1.8% (0.47% excluding cases; ~1 case per 20,000 dogs). The test is also offered for Great Dane and German Terrier, but the variant is the Labrador one: a negative result in those breeds does not rule out their own myopathies (limited data).

- Test Labrador Retriever breeding animals before mating.\n- Do not mate two carriers: 25 %% risk of affected homozygotes.\n- A carrier may be mated with a clear dog; test offspring intended for breeding.\n- In Great Dane and German Terrier, interpret a negative result with caution (it only rules out the Labrador variant).\n- In the face of juvenile muscle weakness, include CNM in the differential diagnosis together with HMLR, EIC and acquired causes.

Differential diagnosis: hereditary myopathy due to type II fibre deficiency (HMLR, no known gene), exercise-induced collapse (EIC, DNM1), congenital/acquired myasthenia gravis, polymyositis and neuropathies. Muscle biopsy with nuclear centralisation points to CNM; the PTPLA test confirms it. No curative treatment: supportive management and physiotherapy.

1. Pelé M et al. 2005, inserción SINE exónica en PTPLA y miopatía centronuclear autosómica recesiva (PMID 15829503)
2. Maurer M et al. 2012, la miopatía centronuclear del Labrador es una mutación fundadora reciente diseminada mundialmente (PMID 23071563)
3. Gentilini F et al. 2011, frecuencia del alelo PTPLA en Labrador Retriever de Italia (PMID 21217042)
4. OMIA:001374 Miopatía centronuclear (PTPLA) del Labrador Retriever