Myotubular Myopathy 1 (Labrador Retriever Type)

General Information: Myotubular Myopathy 1 (MYM1) in Labrador Retrievers manifests as a serious inherited muscle disorder, with symptoms typically emerging between 7 and 19 weeks of age. Initially, affected puppies may appear normal but soon develop noticeable signs such as muscle weakness predominantly in the hind limbs, reduced muscle mass, and distinct difficulties in mobility. These puppies often exhibit a hoarse bark, difficulty in eating, and are noticeably smaller than their littermates, displaying a short, choppy gait and frequent falls. The progression of the disease is rapid, leading from widespread muscle weakness and recurrent collapses to a total inability to stand or lift their heads, often within just a few weeks of symptom onset. Despite the non-painful nature of the disease, the rapid decline in mobility and quality of life generally results in euthanasia of affected dogs between the ages of 3 and 6 months.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog Unlikely Affected

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing for Myotubular Myopathy 1 (MYM1) in Labrador Retrievers identifies mutations in the MTM1 gene, which is crucial for diagnosing carriers and affected individuals. This condition is inherited in an X-linked manner; thus, male puppies require only one mutated gene from their mother to exhibit symptoms, making them more frequently affected. Females must inherit two copies of the mutated gene, one from each parent, to show symptoms. Each male puppy born to a carrier mother has a 50% chance of inheriting the disease. It is highly recommended to avoid breeding carriers to prevent passing on this debilitating mutation. Genetic testing before breeding is essential to identify carriers and make informed breeding decisions, thus helping to eradicate this condition from Labrador Retriever breeding lines. Female dogs who are not carriers of the mutation do not have an increased risk of producing affected offspring, ensuring a healthier future generation.