Fox Terrier Health: Hereditary Issues and Genetic Diversity

The Fox Terrier breed exists in two main types: the smooth haired and the wire haired. Though visually distinct, they share a close genetic lineage, both descending from 19th-century British terriers. The breed's influence also extends to the creation of other terriers, such as the Jack Russell.

Fox Terriers are small dogs standing up to 15.5 inches tall and weighing about 19 pounds. The wire haired variant is more prevalent in the UK, while the smooth haired is considered vulnerable, with fewer than 300 new registrations annually by The Kennel Club.

Average Life Expectancy of Fox Terriers

Fox Terriers tend to live robustly, with an average lifespan of around 13.2 years and some reaching up to 15 years. The most common causes of death are old age and various cancers, reflecting their general hardiness.

Genetic Diversity and Inbreeding Concerns

Genetic diversity is crucial for a breed's long-term health. The coefficient of inbreeding (COI) measures how closely related a dog's parents are. For Wire Fox Terriers, the COI is about 12.4%, which is notably higher than the ideal of 6.25% or less recommended for pedigree dogs. The smooth variety has a slightly better rate at 7.2% but still shows some inbreeding. High inbreeding can increase the chance of hereditary diseases and reduce overall genetic health.

Key Hereditary Health Issues

Despite generally being hardy, Fox Terriers face some hereditary health challenges that prospective owners and breeders should know about:

• Degenerative Myelopathy (DM): Primarily affecting Wire Fox Terriers, DM is a progressive spinal cord disorder causing hind limb weakness and eventual paralysis. This condition is inherited and DNA testing can identify carriers. Alarmingly, nearly 90% of Wire Fox Terriers tested carry the genetic mutation linked to DM, making testing essential prior to breeding.
• Van den Ende-Gupta Syndrome (VDEGS): A rare genetic disorder associated with a mutation in the SCARF2 gene has been found in Fox Terriers. Carriers can be detected by DNA testing, aiding breeders to avoid producing affected puppies.
• Glaucoma: The breed, especially the wire haired type, has a higher incidence of glaucoma, an eye disease that risks vision loss but can often be managed with treatment.

Additional Health Concerns

Beyond the major issues, Fox Terriers may be predisposed to a number of other health conditions, some hereditary but not commonly screened for yet. Examples include:

• Atopy (allergic skin reactions causing itching and discomfort)
• Cataracts and other operable eye problems
• Myasthenia gravis (a neurological disorder causing weakness and lethargy)
• Wolman disease (lipid storage disorder)
• Cardiac problems such as pulmonic stenosis

Health Variations Between Smooth and Wire Haired Types

The smooth haired Fox Terrier has a slightly different health profile, including a reasonable frequency of muscle and nerve degeneration (myelopathy and ataxia) and patellar luxation (kneecap dislocations). Wire haired types may develop haemophilia B and epilepsy, all conditions requiring careful breeding choices to avoid propagation.

Responsible Breeding and Genetic Testing

Because of the hereditary health risks and the breed's limited genetic diversity, responsible breeding practices are essential. Breeders should:

• Use DNA testing to identify carriers of degenerative myelopathy and VDEGS.
• Avoid breeding dogs with high inbreeding coefficients.
• Prioritise health, temperament, and genetic diversity over appearance alone.
• Stay informed of breed health updates from organisations like The Kennel Club.

This approach helps ensure the Fox Terrier remains a healthy, lively, and affectionate companion for generations to come.

Where to Find Healthy Fox Terrier Puppies

If you are looking to find a Fox Terrier puppy, always choose from reputable breeders who provide health clearances and genetic testing. This safeguards your new pet’s wellbeing and supports ethical breeding.

Understanding the Fox Terrier’s hereditary health and genetic diversity challenges equips you to make informed and compassionate decisions about welcoming this breed into your family.