Dr Gary Johnson’s lab at the University of Missouri – College of Veterinary Medicine is pleased to announce that the mutation responsible for development of neonatal ataxia in Jack Russell Terriers has been identified, and a DNA test is now available.
Neonatal Ataxia (NNA) is a progressive, neonatal onset, cerebellar ataxia described in Jack Russell Terriers. Similar to other ataxias known in Jack Russell, Parson Russell, and Russell Terriers, clinical signs consist of intention tremors, loss of coordination, and inability to stand and move in a forward direction. Unlike Spinocerebellar Ataxia (SCA) or Late-Onset Ataxia (LOA), where pups initially appear to be normal and clinical signs begin to appear at 2-6 months of age (SCA) or 6-12 months of age (LOA), with NNA the pups are never able to coordinate movement. As early as 2-3 weeks, when their littermates are beginning to walk, pups affected with NNA become apparent because they cannot move as they should. These clinical signs become more obvious with time, and most affected pups are euthanized at a fairly young age due to lack of quality of life.
A DNA test is now available for NNA. Unlike most DNA tests, this test only determines if the mutation is present or absent, so results are either NORMAL (no mutation), or MUTATION PRESENT (carrier or affected). Because clinical signs are so severe in the affected individuals and present by the time a DNA test can be run, it is easy to see which are clinically normal carriers (with one normal copy and one mutated copy of the gene), verses obviously affected pups with 2 copies of the mutation. Affected pups do not survive to an age where they could be used in a breeding program. Carrier individuals may be used in a careful breeding program to preserve their positive traits, but should only be bred to a mate that has been DNA-tested NORMAL, to avoid risk of producing any affected puppies.
Testing is only available through the Canine Genetics Lab at the University of Missouri at this time. The preferred sample is a blood sample, and dogs that have previously been DNA banked, or have DNA stored due to participation in research or other DNA tests, are eligible for reduced-fee testing.
To send a new sample and request a test for an unsampled dog, or to request testing from a sample already in the U of MO collection for research, DNA banking, or previous testing, contact Liz Hansen at HansenL@missouri.edu to request the correct form.
If you have additional questions, please contact us at HansenL@missouri.edu or 573-884-3712