Arabians, pure and part-bred
Friesians, pure and part-bred
Fell Ponies, Dale Ponies and Gypsy horses, pure and part-bred
Quarter horses and related breeds, pure and part-bred
Saddlebred and related breeds, pure and part-bred
Coat colour tests
Hydrocephalus is a disorder that affects foals during gestation. The foal develops a deformed and distended skull due to a build-up of cerebrospinal fluid around the brain. Foals with hydrocephalus are often stillborn and the birth can be very difficult due to the abnormal size and shape of the foal's head.
Our test is for a mutation in the B3GALNT2 gene (Ducro et al., 2015, DOI 10.1186/s12864-015-1936-z). This mutation was identified in Friesian horses.
Hydrocephalus is an autosomal recessive disorder. Autosomal disorders are equally likely to affect male or female horses, while "recessive" means that a horse needs to inherit the hydrocephalus mutation from both its sire and its dam to be affected. Horses that have inherited the hydrocephalus mutation from just one parent are called hydrocephalus carriers, and do not have physical signs of this disorder.
The hydrocephalus mutation was detected in approximately 8% of the population examined in the scientific paper linked here. We think the prevalence may be a little lower in Australia.