New DNA Test for Dogs: CMM1 in Weimaraners

The DNA test for Congenital Mirror Movement Disorder 1 (CMM1) is now available in our shop. CMM1 is a rare, autosomal recessive movement disorder that has so far only been described in the Weimaraner dog breed.
 

Why is this test important:

The test enables the reliable identification of healthy carriers of the causative mutation.
This allows breeders to:

• preserve healthy carriers in their breeding program
• avoid mating two carriers, thereby preventing the birth of affected puppies

Symptoms in affected animals:

Homozygous affected dogs show the following symptoms from as early as the second week of life:

• coordination disorders
• immobility
• in severe cases, complete paralysis

The hind limbs are often more severely affected. The synchronous hopping with both hind legs is reminiscent of the movement of a rabbit – hence the former name Bunny Hopping Syndrome 1

Genetic cause:

CMM1 is caused by a mutation in the EFNB3 gene.
If it is homozygous, a crucial barrier in the spinal cord is missing, which ensures during embryonic development that nerve pathways only reach the muscles on the correct side of the body.

The result: movement impulses stimulate the limbs on both sides of the body simultaneously.

Prognosis:

CMM1 is untreatable and usually leads to early euthanasia to prevent unnecessary suffering.

Possible uses of the test:

The new CMM1 DNA test enables a reliable and early diagnosis of whether the mutation is present. It is an indispensable tool for breeders of Weimaraners in particular, allowing them to prevent the disease through targeted breeding selection.

Since it cannot be ruled out that the mutation also occurs in other dog breeds, the test is also recommended in the differential diagnosis of puppies with early movement disorders to clarify hereditary causes.

More Information:

Publication: Schwarz, C., et al. (2025). EFNB3 frameshift variant in Weimaraner dogs with a condition resembling a congenital mirror movement disorder. https://doi.org/10.1002/mds.30243

Lexicon: CMM1 - Congenital Mirror Movement disorder 1 

Shop: CMM1 - Congenital Mirror Movement disorder 1