CA stands for Cerebellar Abiotrophy - it is a recessive disease.
It causes lack of balance and coordination and head tremors - symptoms appear between 6 weeks and 4 months of age. Often CA horses cannot get up from a reclining position.
There is no treatment that works well and most owners euthanize CA horses as they become dangerous to handle with their lack of coordination.
It affects Arabs and Arab crossbreds.
Genetic Testing is available.