Dogs are more than man's best friend; at the University of Missouri-Columbia (MU), purebred terriers are helping researchers uncover the genetic roots of life-threatening diseases that affect canines as well as their human owners.

Tibetan terriers can be stricken with a neurological disease known as neuronal ceroid-lipofuscinosis (NCL), a condition which has a human equivalent called Batten disease. Children of parents who carry the rare Batten gene each have a one in four chance of inheriting the as-yet-incurable and fatal condition.

In order to better understand the pathology of the diseases and develop therapies, Dr. Martin Katz, professor of ophthalmology with dual appointments at MU's School of Medicine and College of Veterinary Medicine, is looking to the Tibetan terrier DNA bank for help.

Dr. Katz and his colleagues hope to pinpoint the disease-causing gene defect in this breed by comparing the normal canine genome to the large pool of DNA provided by owners of affected and unaffected Tibetan terriers.

"The organization of genes in a genome is like the organization of books in a library," Dr. Katz explained.

"Genes are arranged in a specific order on a number of different chromosomes, much like books are placed in specific orders on specific shelves in a library. Determining the precise location of a disease-causing mutation within the genome will identify the disease gene, just as going to a specific location on a specific shelf in a library will result in a particular book being located."

Once the NCL mutation in the terriers is identified, scientists will determine whether children with Batten's have the mutation in the corresponding human gene.

Today, Batten's is often not diagnosed until its victims eventually develop a characteristic array of symptoms that include blindness, seizures, cognitive decline and loss of motor function. Discovery of the human gene defect could someday lead to a simple blood test to detect the condition in its early, more treatable stages.

The Tibetan terrier DNA bank was conceived and developed by Stuart Eckmann and Linda Bell, who oversee the Tibetan Terrier Club of America's health programs. Eckmann refers owners of affected dogs to Dr. Katz for examination of retinal and neural tissue. The collaboration has produced a more complete description of the condition than exists in any current textbook.

Recently, the canine DNA bank for genetic studies has expanded to include other dog breeds and diseases, including epilepsy, cancer and Parkinson's disease.