Hypomyelination

Hypomyelination is a congenital disorder caused by the body's inability to produce enough myelin.

Myelin is a fatty substance that covers the axons (the parts of nerve cells that transmit impulses to other cells in the body) and serves two important functions for nerve cells.

It acts as an insulator, protecting the nerve from outside influences, and it aids in the cellular transmission of nervous system actions.

The central nervous system (CNS) is affected, resulting in the most noticeable tremors while a dog is active.

Some breeds have had more cases of CNS hypomyelination than others, including Welsh springer spaniels, Samoyeds, chow chows, Weimaraner's, Bernese Mountain Dogs, and dalmatians.

Male puppies have a greater diagnosis rate in springer spaniels and Samoyed breeds, with symptoms developing within days of birth; females of the same breeds remain mainly asymptomatic carriers of the condition.

In other breeds, there are no gender differences.

Golden retrievers (both sexes) have a greater peripheral nerve system hypomyelination rate, with symptoms emerging in puppies as young as eight weeks.