With intervertebral disc disease (IVDD), degeneration and/or calcification of the intervertebral discs occurs, causing the gelatinous core to press on the spinal cord. This causes pain and paralysis and can damage the nerves. Two types are distinguished: IVDD type 1 and IVDD type 2.
A risk factor for the development of IVDD type 1 has been discovered, an insertion of an FGF4 retrogene at a specific site on chromosome 12. A genetic test is available for this.
The disease occurs predominantly, but not exclusively, in certain short-legged dog breeds. The inheritance is incomplete autosomal dominant.
Juvenile myoclonic epilepsy (JME) is a form of epilepsy with sudden, electroshock-like muscle twitches and seizures. These often occur during the initial sleep phase or can also be triggered by sudden bright light. Most dogs have daily seizures.
The disease occurs in the Rhodesian Ridgeback. The inheritance is autosomal recessive.
Synonym: generalized myoclonic epilepsy
The Leopard Complex leads to extensive white colouration on the hip region or the whole body with pigmented spots ("leopard spots"). There is a great variety of pattern expression: Variable amount of white, variable pigmentation of the spots, spots with and without fringe etc., the exact genetics of the pattern (distribution) is not yet fully understood.
Other Characteristic traits are white stripes on hooves, visible white sclera in eyes, speckled/mottled skin around the eyes, muzzle and genital regions, progressive “varnish roan” coat color.
The pattern 1 mutation can strongly influence the amount of white in leopard spotted horses.
Leopard-Complex is associated with the Congenital Stationary Nightblindness (CSNB) if two copies (LP/LP) are present.
Malignant Hyperthermia (MH) is also known as "Canine Stress Syndrome (CSS)". Affected animals exhibit symptoms such as high fever, muscle cramps/stiffness, or respiratory distress. Some affected animals appear healthy, but exhibit the above symptoms under stress.
The disease occurs in many breeds. The inheritance is autosomal dominant. It occurs when one or both copies of the gene (n/MH or MH/MH) are affected by the mutation.
Malignant hyperthermia (MH) causes anesthesia- or stress-induced muscle rigidity with fever and respiratory distress. MH results in death of the horse in approximately 34% of cases.
The disease occurs in many breeds. The inheritance is autosomal dominant.
Merle coloured dogs show a pattern of darker and lighter patches which appears random. The eyes may be lighter or blue in colour.
The colour is caused by the M allele of the M locus. Homozygous animals (M/M) have severe health problems such as deafness, blindness and organ problems.
Mushroom is a coat colour unique to the Shetland Pony, where phaeomelanin (chestnut colour) is lightened to a light sepia shade. Mushroom can also slightly affect the coat colour of ponies with bay base colour.
The colour is inherited autosomal recessively. Animals with one copy of the mutation (N/mu) show no dilution. Only animals with two copies of the mutation (mu/mu) show the Mushroom dilution.