Muscular hypertrophy (double muscling)

Disease overview

Muscular hypertrophy is a disease that affects muscle growth. Muscle growth is typically halted by a gene that encodes for a protein, called myostatin, that typically stops muscle growth. A mutation in this gene causes decreased levels of myostatin, which leads to heavily-muscled, athletic dogs.

Gene name

MSTN

Inheritance

Autosomal dominant with incomplete penetrance

Signs and symptoms

Affected dogs will have double muscling that gives them a heavily-muscled and athletic appearance. Muscle cramping is another potential symptom.

How is it diagnosed

A veterinarian will conduct a thorough exam, including a review of health history and any clinical signs. Diagnostics will likely include blood tests. Genetic testing can determine if there is an underlying genetic cause.

Breeds at higher risk

Citations

Mosher DS, Quignon P, Bustamante CD, Sutter NB, Mellersh CS, Parker HG, Ostrander EA. A mutation in the myostatin gene increases muscle mass and enhances racing performance in heterozygote dogs. PLoS Genet. 2007 May 25;3(5):e79. doi: 10.1371/journal.pgen.0030079. Epub 2007 Apr 30. PMID: 17530926; PMCID: PMC1877876.

Shelton GD, Engvall E. Gross muscle hypertrophy in whippet dogs is caused by a mutation in the myostatin gene. Neuromuscul Disord. 2007 Oct;17(9-10):721-2. doi: 10.1016/j.nmd.2007.06.008. Epub 2007 Jul 24. PMID: 17651971.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.