What is Ataxia? The term ataxia is derived from the Greek meaning “without order”. Ataxia refers to a lack of normal coordination of movement. There are different types of ataxia, but we are focusing on cerebellar ataxia, which is in the portion of the brain that fine-tunes movement.
There two known types of ataxia mutations in the Jack Russell Terrier, Spino-cerebellar Ataxia (SCA) and Neonatal Ataxia (NNA).
Neonatal Ataxia is seen as early as two weeks of age. Pups get separated easily from the litter, they struggle with an uncontrolled head motion in an effort to achieve forward motion to return to the litter.
If they survive until four weeks of age they master standing with a very wide stance and have a drunken, staggering gait, with frequently having a goose stepping movement of the front limbs. When eating they peck their food, raising their head quickly to avoid tumbling forward. They spend most of their time and energy trying to upright themselves after falling. While they have a desire to run and play they are unable to do so. Most pups are euthanized soon after diagnosis due to the lack of quality of life. Breeders who have experienced this horrific disease will tell you how sad it is to witness a puppy with the terrier drive and determination fail at trying to be normal.
Spino-cerebellar Ataxia can start showing signs as early as 12 weeks, but in most cases symptoms occur between 6-9 months. Some may move well in a straight line, but stumble or fall when making fast turns, climbing stairs, or attempting to catch a ball. You will see signs of a staggered gait, lack of balance, rolling when running, and eventually the onset of seizures. The reported SCA cases the RF have been involved with, all have myokymia seizures, it is these uncontrollable seizures that deteriorate the quality of life and death is certain.
While there is a test available for Late On-set Ataxia we have never seen LOA in the JRT. Researchers at the University of Missouri and Animal Health Trust did not find the LOA gene mutation in the Jack Russell Terrier. While some breeders have decided to test for LOA, all have tested Normal and those are included in the Health Registry.
For information on where to test for Ataxia as well as other genetic diseases that affect the Jack Russell please visit the RF website at www.jrt-research.com.
Debbie Johnson, Research Foundation