Hessen

Dominant white is a variable white spotting pattern caused by many different mutations in the KIT gene. The VGL tests for the five most common mutations known as W5, W10, W13, W20, and W22. Homozygosity for W5, W10, W13 or W22 is thought to be non-viable.

Cream is a dilution that causes the palomino, buckskin, smoky black, cremello, perlino, and smoky cream coat colors.

The agouti gene controls the distribution of black pigment, and determines whether a horse will have a bay or black base coat color.

Fragile foal syndrome (FFS) type I, formerly known as Warmblood fragile foal syndrome (WFFS) type I, is a recessive inherited connective tissue defect characterized by hyperextensible joints and abnormally thin fragile skin and mucous membranes.