The Disease
Myotonia congenita is a hereditary pathogenic condition affecting skeletal muscle ion channels and is characterized by a delay of relaxation ot the skeletal muscles following an electical or mechanical stimulus or after cessation of voluntary activity. Myotonia congenita results from genetic defects in the skeletal muscle chloride ion channel and the ensuing reduced chloride ion conductance across the sarcolemma. Myotonic Miniature Schnauzers have hypertrophic skeletal muscles, difficulty in rising after a period of rest, a stiff and stilted gait when walking, and a bunnyhop type movement when running. In addition, there are increased respiratory sounds, difficulty when swalling, ptyalism, dental abnormalities and superior prognathism.

The Trait of Inheritance
Myotonia congenita in Miniature Schnauzers is an inherited autosomal recessive trait. This means that a dog can be clear (homozygous normal), affected, or a carrier (heterozygous). The carriers can spread the diseased gene in the population. Therefore, reliable information on non-affected dogs is the key to controlling this disease.

The mutation-based gene test and its advantages
Progress in molecular genetics has allowed the identification of the gene mutation responsible for Myotonia congenita in Miniature Schnauzers.
By DNA testing, the responsible mutation can be shown directly. This method provides a very high accuracy test and can be done at any age. It offers the possibility to distinguish not only between affected and clear dogs, but also to identify clinically healthy carriers. This is an essential information for controlling the disease in the breed, as carriers are able to spread the disease in the population, but can not be identified by means of common laboratory diagnostic.
If a particularly valuable dog turns out to be a carrier, it can be bred to a non-affected animal, and non-carrier puppies can be saved for the next round of breeding.

Requirements
The tests are performed out of  EDTA whole blood (1 ml). Testing is performed a few times per week at Laboklin. The results are due about one week after arrival of the sample in our laboratory.