Adrenoleukodystrophy (ALD) is a disease linked to the X chromosome. It is a result of fatty acid buildup caused by peroxisomal fatty acid beta oxidation which results in the accumulation of very long chain fatty acids in tissues throughout the body. The most severely affected tissues are the myelin in the central nervous system, the adrenal cortex, and the Leydig cells in the testes. The long chain fatty acid buildup causes damage to the myelin sheath of the nerves of the brain, resulting in seizures and hyperactivity. Other symptoms include problems in speaking, listening, and understanding verbal instructions. Clinically, ALD presents as a heterogeneous disorder, showing several distinct phenotypes, and no clear pattern of genotype–phenotype correlation. As an X-linked disorder, ALD presents most commonly in males; however, approximately 50% of heterozygote females show some symptoms later in life. Approximately two-thirds of ALD patients will present with the childhood cerebral form of the disease, which is the most severe form. It is characterized by normal development in early childhood, followed by rapid degeneration to a vegetative state. The other forms of ALD vary in timing of onset and in clinical severity, ranging from adrenal insufficiency alone to progressive paraparesis in early adulthood. ALD is caused by mutations in  ABCD1, a gene located on the X chromosome that codes for ALD, a peroxisomal membrane transporter protein. The exact mechanism of the pathogenesis of the various forms of ALD is not known.
Known causes for head tilt in domestic animals include:

Encephalitozoon cuniculi (or E. cuniculi) infection in rabbits
parasitic infestation by the nematode (roundworm) Baylisascaris procyonis in rabbits
Inner ear infection
Hypothyroidism in dogs
Disease of the VIIIth cranial nerve the N. Vestibulocochlearis through trauma, infection, inflammation or neoplasia
Disease of the brain stem through either stroke, trauma or neoplasia
Damage to the vestibular organ due to toxicity, inflammation or impaired blood supply
Geriatric vestibular syndrome in dogs

Notes
References
External links
Head Tilt: Causes and Treatment