CANINE FUCOSIDOSIS

 

Is a severe, progressive and ultimately fatal disease that affects the English Springer Spaniel. It is an inherited condition in the breed and has been reported in the UK, Europe and Australia. It is inherited through an autosomal recessive trait.

The disease affects young adults, usually between 18 months and 4 years of age, and is characterised by nervous signs that progress over

a period of several months. These signs include inco-ordination and ataxia (loss of control of movement), change in temperament, loss of learned behaviour, loss of balance, apparent deafness, visual impairment and varying degrees of depression.

The inco-ordination and ataxia affects all four legs and is mostly evident when affected animals are walking on slippery surfaces or attempt more complicated movements such as turning. In addition, affected dogs lose weight and may suffer from swallowing difficulties and sometimes regurgitation of food.

 

The disease is caused by the absence of an enzyme called alpha-L-fucosidase. This enzyme is one of many required to break down complex compounds intosimple molecules that the body can use. When the enzyme is absent, the pathway is blocked and the more complex compounds build up in the cells of the affected animal. These substances accumulate in lymph nodes, liver, pancreas, kidney, lungs

and bone marrow, but it is the accumulation in the brain and peripheral nerves that is most important since it interferes with normal function, giving rise to the clinical signs described above, eventually resulting in death.


Clinical signs

Signs include incoordination and ataxia (loss of control of movement), change in temperament, loss of learned behaviour, loss of weight, loss of balance, apparent deafness, visual impairment and varying degrees of depression.

How it is inherited

The disease is described as an autosomal recessive condition. This means that a dog must inherit two copies of an abnormal gene (one from its mother and one from its father) before its health is affected. A dog that inherits only one copy of the abnormal gene (from its mother or its father) will have no signs of the disease, but will be a carrier and may pass the gene on to any offspring.


Sire

  Dam   Offspring
         
Clear
x
Clear
>
100% Clear
         
clear
x
carrier
>
50%  Clear + 50% carriers
         
clear
x
affected
>
100% carriers
         
carrier
x
Clear
>
50%  Clear + 50% carriers
         
carrier
x
carrier
>
25% clear + 25% affected + 50% carriers
         
carrier
x
affected
>
50% carriers + 50% affected
         
affected
x
Clear
>
100%  carriers
         
affected
x
carrier
>
50% carriers + 50% affected
         
affected
x
affected
>
100% affected