Startle disease / hyperekplexia (SLC6A5-related) - Old English Sheepdog

What does this test examine?

This genetic test analyses a c.1300del in SLC6A5 in the Miniature American Shepherd and Miniature Australian Shepherd. The condition is known as startle disease, hyperekplexia, exaggerated startle response, stimulus-triggered muscle stiffness and SLC6A5-related hyperekplexia.

What does this condition mean?

SLC6A5 encodes part of the glycine transporter, which helps transmit inhibitory nerve signals in the brain stem and spinal cord. When two copies of the tested deletion are present, this inhibitory signalling is disrupted. Affected puppies can suddenly stiffen or collapse after sound, touch or excitement while remaining conscious. Severe episodes can interfere with breathing and feeding.

Inheritance and result

This condition is autosomal recessive. A dog with one copy is a carrier and can pass the variant on. A dog with two copies is genetically affected for the tested form of startle disease.

Practical value of this test

This test is valuable for breeders because carriers can appear healthy, yet two carriers together can produce affected puppies. The result makes it possible to identify carriers and plan matings so puppies do not inherit two copies of the variant.

• Identifies clear dogs, carriers and genetically affected dogs.
• Helps avoid high-risk matings between two carriers.
• Supports rapid genetic clarification in puppies with sudden stiffness or exaggerated startle responses.
• Gives breeders clear information for line selection and communication with puppy buyers.