Lexicon

Hair length is a trait in many dog breeds, which is important in the selection of intended matings. There is usually a short coat type and a long coat type.

Which genetic type the dog has, i.e. which coat length it develops, can be determined by a genetic test (FGF5 gene).

This coat structure occurs in many different breeds.

Genetic Test: available in Shop

Hairlessness (ectodermal dysplasia) results in bald (hairless) patches all over the body. The trait occurs in a few breeds, e.g. Chinese Crested Dog and Mexican Naked Dog. It is homozygous lethal. Dogs with two copies of the mutated gene die before birth.

Harlequin dogs show black patches on a white base coat. It is a modified version of the Merle colouration. This means that all dogs showing the Harlequin pattern in the phenotype also have one copy of the Merle mutation. Dogs without the mutation for Merle (m/m), can be carriers for Harlequin.

The colour is caused by the H allele of the H locus. Homozygous animals (H/H) die before birth.

Genetic Test: available in Shop

Hereditary Equine Regional Dermal Asthenia (HERDA) is caused by the presence of abnormal collagen in the skin. This results in skin detachment, severe lesions, ulcerations and wound healing problems.

The disease occurs in the Quarter Horse and related breeds. It is inherited autosomal recessively.

Synonym: Ehlers-Danlos syndrome, hyperelastosis cutis

Hereditary Nasal Parakeratosis (HNPK) is a differentiation disorder of the skin cells (keratinocytes) in the area of the dog's nose. Affected dogs show firm scabs on the upper nose leather and thus a risk of cracks and fissures on the nose.

The pre-damaged skin can be more easily infected by pathogens, which can lead to complications. The animals are otherwise healthy.
The disease occurs in the Labrador Retriever. The inheritance is autosomal recessive.

Genetic Test: available in Shop

Also in the Labrador Retriever A package (DRC P1)

Hoof Wall Separation Disease (HWSD) is characterized by a defect in the connective tissue of the hoof wall. Affected animals have hooves that can be brittle and crack easily. The mutation was originally identified in Connemara ponies but has not also been found in Tinkers, Cobs, American Miniature Horses, and German Riding Ponies. It has an autosomal recessive mode of inheritance.

Genetic Test: available in Shop

In hydrocephalus, cerebrospinal fluid accumulation in the brain leads to enlarged skull and death of the foal. The disease occurs in Friesian horses and is inherited autosomal recessively.

Hyperkalemic Periodic Paralysis (HYPP) is caused by a malformed channel protein in skeletal muscle cells and results in temporary paralysis due to malfunctioning signal transmission from the brain to the muscles/organs.

The disease occurs in the Quarter Horse and related breeds. The inheritance is incomplete autosomal dominant.

In Hyperuricosuria and Hyperuricaemia (HUU), dogs excrete uric acid instead of allantoin in their urine. This causes increased formation of urinary stones, which can lead to problems.

The disease occurs in many breeds. It is inherited autosomal recessively.

Synonym: Urolithiasis

Genetic Test: available in Shop (in Labrador Retriever B package)