Table 3.
Characterized Genetic Diseases of the Domestic Horse
| Disease | Major Breed(s) | Chromosome | Gene | Mutation | Inheritance | Testing* |
|---|---|---|---|---|---|---|
| Hyperkalemic Periodic Paralysis (HYPP) (Cannon et al. 1995; Naylor et al. 1999; Rudolph et al. 1992a; Rudolph et al. 1992b) |
Quarter Horse Paint QH-related |
11 | SCN4A | C to G substitution Phe to Leu substitution |
Autosomal Co-dominant | Y |
| Polysaccharide Storage Myopathy (PSSM) (McCue et al. 2009; McCue et al. 2008a; McCue et al. 2008b) |
Quarter Horse QH-related Warmbloods Drafts |
10 | GSY1, +/− others | G to A substitution Arg to His substitution |
Autosomal Dominant | Y |
| Malignant Hyperthermia (Aleman et al. 2005; Aleman et al. 2009) |
Quarter Horse | 10 | RYR1 | C to G substitution Arg to Gly substitution |
Autosomal Dominant | Y |
| Glycogen Branching Enzyme Deficiency (GBED) (Valberg et al. 2001; Ward et al. 2004; Ward et al. 2003) |
Quarter Horse | 26 | GBE1 | C to A substitution Premature stop codon |
Autosomal Recessive | Y |
| Severe Combined Immunodeficiency (SCID) (Bailey et al. 1997; Shin et al. 1997; Wiler et al. 1995) |
Arabian | 9 | DNA-PKcs | 5 bp deletion Unstable protein |
Autosomal Recessive | Y |
| Junctional Epidermolysis Bullosa (JEB) (Graves et al. 2008; Lieto and Cothran 2003) |
American Saddlebred | 8 | LAMA3 | 6589 bp deletion Dysfunctional protein |
Autosomal Recessive | Y |
| Junctional Epidermolysis Bullosa (JEB) (Milenkovic et al. 2003; Spirito et al. 2002) |
Belgian French Drafts |
5 | LAMC2 | C insertion Premature stop codon |
Autosomal Recessive | Y |
| Hereditary Equine Regional Dermal Asthenia (HERDA) (Tryon et al. 2007; Tryon et al. 2005; White et al. 2004; White et al. 2007) |
Quarter Horse | 1 | PPIB | Missense mutation Gly to Arg substitution |
Autosomal Recessive | Y |
| Overo Lethal White Syndrome (OLWS), Ileocolonic Aganglionosis (Metallinos et al. 1998; Santschi et al. 2001; Yang et al. 1998) |
Paint | 17 | EDNRB | TC to AG substitution Ile to Lys substitution |
Autosomal Recessive | Y |
| Gray Horse Melanoma (Pielberg et al. 2008) |
Many | 25 | STX17 | Duplication in intron 6 | Autosomal Dominant | Y |
| Lavender Foal Syndrome (Brooks et al. 2010) |
Arabian | 1 | MYO5A | G138235715del Single bp deletion in exon 30 |
Autosomal Recessive | N |
*
Y, testing available commercially; N, testing not yet available commercially, but expected soon.