Categories: Behaviour / neurological phene

Mendelian trait/disorder: yes

Mode of inheritance: Z-linked recessive

Disease-related: yes

Key variant known: no

Species-specific symbol: px

Clinical features: Cole (1958): "The pullet chicks which receive the gene px from their sire hatch normally and show no disturbance of behavior until about two weeks of age or older. At that time, following sudden auditory or visual stimulation, an occasional chick will start to move quickly across the floor of the pen or battery, as if excited, and then fall, with legs rigidly extended, head thrown back, wings beating violently, while the entire body is in a state of tetany and tremors ... . The tetany and tremors continue for about 10 seconds, after which the entire body becomes completely relaxed, the eyes are closed, and the chick lies quietly. ... Eventually all of them succumb, usually by 14 to 15 weeks of age."

Pathology: Cole (1958): "No pathological changes in gross structure have been recognized nor have any microscopic lesions been seen in sections from the cerebellum."