Cerebellar abiotrophy

Cerebellar abiotrophy (English Cerebellar Abiotrophy, CA), also known as Cerebellar Cortical abiotrophy called (CCA ) or cerebellar atrophy, is an inherited neurological disease of animals that occurs most frequently in certain horse and dog breeds. In this disease there is a death of Purkinje cells in the cerebellum. It occurs mainly in young animals in the form of balance and motor deficits.

Affected breeds

Affected breeds of horses are Arabs and their hybrids, miniature horses, the Gotland ponies and possibly the Oldenburg. Among domestic dogs Cerebellar abiotrophy occurs mainly at the Gordon Setter, Wire-haired Collie, the Bernese Mountain Dog, Kerry Blue Terrier and the Brittany Spaniel. Furthermore, the disease in Siamese cats, Angus, Polled Hereford, Charolais and Holstein - Friesian cattle, Merino and Wiltshire Horn sheep and Yorkshire pigs occurs.

Formation

Cerebellar abiotrophy develops when certain nerve cells die in the cerebellum ( the so-called Purkinje cells ) by programmed cell death. The cerebellum controls all movements; the Purkinje cells particularly affect balance, coordination and fine motor skills, and facilitate communication between the different layers of the cerebellar cortex.

In horses, the Purkinje cell start in most cases within the first 90 days after birth to die. The disease is usually seen when the foal is younger than six months. In some cases, however, the disease is so gradual that the owner or caregiver notice any problem until the horse is two or three years old. Most of these cases will fall when the settling triggers stress, or if the young horse is given in Show or advanced training.

Cerebellar abiotrophy in horses was originally viewed as a form of cerebellar hypoplasia and was designated according to older scientific literature. There are diseases that cause cerebellar degeneration other forms, but the loss of Purkinje cells is a clear sign of cerebellar abiotrophy.

Clinical signs (symptoms )

• Uncontrollable movements (ataxia) or balance problems,
• Awkward widely splayed front legs close together standing fetlock joints,
• A tremor of the head (intention tremor),
• Hyperactivity,
• Lack of menace response
• Third eyelid ( nictitating membrane ) shows delayed or no wink,
• Rigid or excessive pace of the shoulder in the forehand,
• Coarse or jerky head jerking when to suck in motion or in very young animals while trying to
• Standing to go on bent hooves or attempts so, sometimes cross-legged,
• Poor depth perception and assess general inability, space and distance.

In more severe cases, foals / horses may have difficulty getting up or when straight rein back. Tight turns can lead to falling down or sideways wegrutschenden hind legs. Affected horses are prone to accidents, tend to run into fixed objects, fall while climbing sideways and often beat his head against, which can lead to erroneous impression that a serious head injury had caused the ataxia. The horse in question has normal intelligence, clear view, good appetite and shows no muscular atrophy.

Affected dogs are completely unremarkable birth. Only after months or even years to develop insidiously movement disorders, namely when many Purkinje cells are correspondingly died.

Inheritance

In horses Cerebellar abiotrophy is a monogenic autosomal recessive. Horses that carry only one copy of the gene, it can hand down to their descendants, but they themselves are without any clinical signs of the disease.

Research

The genetic basis of CA is currently under investigation at the Veterinary Genetics Laboratory at the University of California, Davis. While the specific CA- causing mutation is still unknown, a group of adjacent genetic marker has been identified which can be used as test DNA for CA. Breeders who want to test their horses before mating, can use the CA test to avoid the mating of two carriers.

Results of the test are displayed as follows:

• N / N: Normal. Horse does not have a marker associated with CA.
• N / CA: carrier (1 copy of the CA allele ). Horse has associated with CA and is considered to be marker phenotypically normal and as a carrier of the disease allele.
• CA / CA: hit ( 2 copies of the CA allele ).