In other species: Nile tilapia , Japanese flounder , Mallard , rock pigeon , chicken , pig , taurine cattle , goat , sheep , rabbit , pacu , water buffalo , Japanese quail , red seabream , yellow catfish

Categories: Muscle phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 601788 (gene) , 614160 (trait)

Links to relevant human diseases in MONDO:

• MONDO:0013598: myostatin-related muscle hypertrophy

Single-gene trait/disorder: yes

Mode of inheritance: Autosomal

Disease-related: no

Key variant known: yes

Year key variant first reported: 2007

Cross-species summary: Abnormal increase in muscular tissue caused entirely by enlargement of existing cells (in contrast to muscular hyperplasia, in which the abnormal increase in muscular tissue is due to the formation and growth of new, normal muscle cells)

Species-specific name: Hypermuscularity; gross muscle hypertrophy; 'bully' whippets

Species-specific description: In addition to the occurrence of natural variants for this trait, variants have been created artificially (e.g. Zou et al., 2015): Genetically-modifed organism; GMO.

Genetic engineering: Yes - in addition to the occurrence of natural variants, variants have been created artificially, e.g. by genetic engineering or gene editing
Have human generated variants been created, e.g. through genetic engineering and gene editing

Clinical features: Affected dogs show an unusual amount of muscularity, especially in the neck and legs. They are broad chested and typically don’t conform to the breed standard (slim, long neck, pointed snout) (Mosher et al., 2007). Dogs with a single copy of the mutation show a smaller degree of hypermuscularity are significantly faster than homozygous wild-type whippets (Mosher et al., 2007). Hence, being heterozygous for the mutation is considered performance enhancing. For whippets with a double copy of the mutation, there is little evidence about potential associated health risks. It has been anecdotally reported amongst breeders that affected whippets are otherwise generally healthy and only suffer from occasional muscle cramps and a distinctive overbite (Mosher et al., 2007). IT thanks DVM student Lucas Anderson, who provided the basis of this contribution in May 2023.

Breed: Whippet (Dog) (VBO_0201421).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene: