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• Documented Genes
  
• What is a documented gene?
  
• Black/Red (MC1R)
  
• Bay (ASIP)
  
• Cream/Pearl (SLC45A2)
  
• Dun (TBX3)
  
• Gray (STX17)
  
• Silver (PMEL17)
  
• Champagne (SLC36A1)
  
• Roan/Tobiano/Sabino/White Spotting (KIT)
  
• Splash White (MITF/PAX3)
  
• Leopard Complex (TRPM1/ECA3P)
  
• Frame (EDNRB)
  
• Tiger Eye (SLC24A5)
  
• Height Regulation (HMGA2/LCORL)
  
• Mushroom (MFSD12)
  
• Hypothetical Genes
  
• What is a hypothetical gene?
  
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Leopard Complex (TRPM1/ECA3P)

• Last updated: 2026-01-21

  About LP:

  Common Names: Leopard, Leopard Complex, Appaloosa, Spotted, Tiger 

  Scientific Name: Transient Receptor Potential Cation Channel, Subfamily M, Member 1 (TRPM1)

  Equine Chromosome: 1

  
  

  About PATN1:

  Common Names: Pattern 1, Blanket

  Scientific Name: RING finger and WD repeat domain 3 (RFWD3)

  Equine Chromosome: 3

  
  

  General Overview:

  Leopard spotting is the general term for a roany polka dot marking pattern in horses, primarily known from the Appaloosa breed but also found in breeds like the Knabstrupper, Noriker and Miniature horses. Its expression is turned on or off by the LP allele of TRPM1. Horses with the LP allele get progressively whiter with age, with boney areas on the face and joints turning white last.[1]
  
  The PATN1 mutation of RFWD3 modifies the expression of LP. Horses with a single copy of PATN1 tend to have a blanket of white, ranging from a small area over the hips, to a large blanket over all of the hips, back and shoulders. Horses with two copies tend to have very large blankets or even be entirely covered in white. [2] PATN1 is the major factor controlling blanket size but does not fully explain all blanket size variation in LP horses. Many other undocumented factors seem to also impact blanket size. 

  
  

  Horses with one copy of LP and a blanket will show polka dots of the base color clustered in and around that blanket. Horses with two copies of LP will have the blanket but few to no polka dots.

  
  

  For clarity HorseGeneticsGame.com uses the term "appaloosa" to describe all LP horses as "spotted" is already used to describe the white spotting mutation.

• Expression:

  All LP horses will have “LP characteristics” which include mottled skin, stripped hooves, and a viable white sclera, but not all LP horses display varnishing, a blanket, or spots. These characteristic only horses are sometimes called “solid” or "carrier" horses.

  
  

  Varnish: A horse with LP characteristics and white hairs throughout the body that increase with age.  Varnish horses can be distinguished from true roans because varnish avoids boney areas like joints and prominent facial bones. True roan is even over the entire body but absent from the head, legs, mane and tail. An LP horse may be “varnish” in conjunction with any blanket size. For example a “varnish snowcap”.

  
  

  Lacey Blanket: A very small lacey pattern of white over the hips. It may be very difficult to detect heterozygous LP spotting on these horses.

  
  

  Spotted Blanket: A wash of completely white hair over pink skin that originates from the top of the hips and can cover just the hind quarters or be as large as the entire hips, torso and shoulder area. The blanket is accented throughout by polka dots. These horses are heterozygous for LP.

  
  

  Snowcap Blanket: Like a spotted blanket but lacks the polka dots. If present at all, they are very small and infrequent. These horses are homozygous for LP. 

  
  

  Near Leopard: A horse with a very extensive blanket that extends into the neck and legs, accented by polka dots. These horses are heterozygous for LP.

  
  

  Near Fewspot: Same as a near leopard but lacks the polka dots. If present at all they are very small and infrequent. These horses are homozygous for LP.

  
  

  Leopard: A horse whose entire body is covered in blanket marking, giving them the appearance of an all white horse with polka dots of color. These horses do not tend to show visible varnishing with age. These horses are heterozygous for LP.
  
  Fewspot: Same as a leopard but lacks the polka dots. If present at all they are very small and infrequent. These horses are homozygous for LP. 

• Night Blindless:

  The LP gene has been found to be the direct cause of congenital stationary night blindness (CSNB). All LP/LP lack the ability to see at night so extra consideration should be given to their environment to prevent night time injury. Horses with only one copy of LP do not seem to be impacted. [1] There is no evidence blanket size impacts CSNB status. LP/LP horses have no negative health impacts in HorseGeneticsGame.com

• Citations:

  1. Bellone RR, Brooks SA, Sandmeyer L, Murphy BA, Forsyth G, Archer S, Bailey E, Grahn B. Differential gene expression of TRPM1, the potential cause of congenital stationary night blindness and coat spotting patterns (LP) in the Appaloosa horse (Equus caballus). Genetics. 2008 Aug;179(4):1861-70. doi: 10.1534/genetics.108.088807. Epub 2008 Jul 27. PMID: 18660533; PMCID: PMC2516064.  https://www.researchgate.net/publication/51431473...s 
  2. Holl HM, Brooks SA, Archer S, Brown K, Malvick J, Penedo MC, Bellone RR. Variant in the RFWD3 gene associated with PATN1, a modifier of leopard complex spotting. Anim Genet. 2016 Feb;47(1):91-101. doi: 10.1111/age.12375. Epub 2015 Nov 16. PMID: 26568529. https://pubmed.ncbi.nlm.nih.gov/26568529/ 

• Examples:

  Characteristic/Solid, Varnish, Lace Blanket

  

  
  

  Spotted Blanket LP/lp, Snowcap Blanket LP/LP

  

  
  

  Near Leopard LP/lp, Near Fewspot LP/LP

  

  
  

  Leopard LP/lp, Fewspot LP/LP