Genetic Diseases in Chihuahuas

Chihuahuas are a generally healthy and hardy breed. These small dogs weigh less than six pounds fully grown, according to the Dog Breed Info Center, and stand between six and nine inches at the shoulder. They have few serious health issues. However, some chihuahuas are born with genetic abnormalities that cause a variety of physical problems.

  1. Patellar Luxation

    • Patellar luxation, or slipped kneecaps, is an inherited disorder that affects chihuahuas, as well as many other small and toy-sized breeds. The Web Vet explains that the kneecap fits into a groove on the front part of the leg, and it slides up and down depending upon the motion of the leg. Sometimes the kneecap slips, or luxates, out of its groove. This condition is called patellar luxation. Dogs with this disorder have difficulty walking. They may hop, skip or avoid putting any weight on the affected leg. The Web Vet website warns that patellar luxation causes arthritis in the knee. Most chihuahuas do not require treatment for this condition. Dogs with severe cases of patellar luxation are treated with weight management, anti-inflammatory medication or surgery.

    Glaucoma

    • The Canine Inherited Diseases Database indicates that chihuahuas are susceptible to an eye disorder called goniodysgenesis glaucoma, a painful condition that leads to blindness. This disorder develops in dogs that have an abnormal piece of tissue in the area of the eye where drainage normally takes place. Excessive fluid puts pressure on the inside of the eye. This damages the retina and optic nerve. The veterinarian diagnoses the condition by using a machine called a tonometer to measure the pressure inside the eye. Excessive pressure generally indicates glaucoma. Glaucoma is treated with a combination of medication and surgery.

    Hydrocephalus

    • According to Chihuahua Information Online, chihuahua puppies are occasionally born with a condition called hydrocephalus, or water on the brain. Many puppies with severe hydrocephalus are stillborn or die shortly after delivery. There is no cure for this often-fatal disorder. Chihuahuas with hydrocephalus have abnormally large heads, eyes that gaze outward instead of forward and physical and mental retardation. They do not grow, develop or learn as quickly as healthy dogs. The symptoms of mild hydrocephalus are controlled with prednisone and lasix.

    Mitral Valve Disorder

    • Mitral valve disorder is a genetic heart disease. The left atrioventricular valve, or mitral valve, does not pump blood correctly. The blood backflows into the valve. The early symptoms of mitral valve disorder are breathing difficulties, coughing and an inability to exercise for extended periods of time. Later symptoms include weakness or fainting. The condition leads to heart failure. Low-sodium diets, minimal exercise and medication are used to prolong the dog's life, according to the Canine Inherited Disorders Database.