X-linked ichthyosis X-linked ichthyosis X-linked ichthyosis (XLI) (also known as ") is a skin condition caused by the hereditary deficiency of the steroid sulfatase (STS) enzyme that affects 1 in 2000 to 1 in 6000 males. XLI manifests with dry, scaly skin and is due to deletions or mutations in the "STS" gene. XLI can also occur in the context of larger deletions causing contiguous gene syndromes. Treatment is largely aimed at alleviating the skin symptoms. The term is from the Ancient Greek 'ichthys' meaning 'fish'. The major symptoms of XLI include scaling of the skin, particularly on the neck, trunk, and
Henneke horse body condition scoring system before the race due to their high exercise levels, possibly also leading to a decrease in muscle mass. They explain the differences of results between the studies in part in that the participating horses of the 1990 Purina Race of Champions have had to qualify before and present a more highly-performing field of horses. Both Tevis Cup studies found that horses with a higher body condition score had, however, a significantly higher rate of not finishing the race due to lameness. Horses on pasture should enter the winter season at a body condition score of 6 or 7. On extremely