HEALTH
ROTTWEILER
Myotubular Myopathy is sex-linked inherited muscle disease that occurs in Labrador Retriever and Rottweiler. Symptoms are similar to Centronuclear Myopathy (CNM) / Hereditary Myopathy.
Affected puppies appear normal at birth but they start showing symptoms between 7 and 19 weeks of age. Symptoms include progressive skeletal muscle atrophy, muscle weakness especially in the hind limbs, small stature compared to unaffected littermates, puppies can walk with short choppy strides, collapsing after few strides, difficulty eating due to weakness in mastication muscles, which may lead to dropped jaws, hoarse bark.
The disease progresses rapidly and puppies become unable to stand or raise their heads by 3-4 weeks after the start of the symptoms.
Affected dogs are usually euthanized between 15-26 weeks of age.
Due to the X Linked recessive mode of inheritance, males can either be clear or affected, where as females can be clear, carriers or affected. Females are rarely affected because affected males are usually euthanized at young age. The disease is primarily found in males. Testing enables breeders to identify clear, carrier and affected dogs and help in reducing the occurrence of the disease.
XLMTM is considered rare and we currently have no information about its prevalence in the UK.
Male:
Clear
Genotype: N [ normal ]
The dog is noncarrier of the mutant gene.
The dog will never develop X-linked Myotubular Myopathy (XLMTM) and therefore it can be used in breeding and should only be bred to clear females.
Affected
Genotype: XLMTM [ mutant ]
The dog carries the mutant gene and will pass it its entire female offspring.
The dog will develop X-linked Myotubular Myopathy (XLMTM) and will pass the mutant gene to its entire female offspring
Female:
Clear
Genotype: N / N [ Homozygous normal ]
The dog is noncarrier of the mutant gene.
The dog will never develop X-linked Myotubular Myopathy (XLMTM) and therefore it can be used in breeding and should only be bred to clear females.
Carrier
Genotype: N / XLMTM [ Heterozygous ]
The dog carries one copy of the mutant gene and one copy of the normal gene.
The dog will never develop X-linked Myotubular Myopathy (XLMTM) but since it carries the mutant gene, it can pass it on to its offspring.
Affected
Genotype: XLMTM / XLMTM [ Homozygous mutant ]
The dog carries two copies of the mutant gene and therefore it will pass the mutant gene to its entire offspring.
The dog will develop X-linked Myotubular Myopathy (XLMTM) and will pass the mutant gene to its entire female offspring