The carrier frequency and incidence of alpha thalassemia vary by the type and population. Carrier frequency of this condition is reported to be the highest in individuals of Southeast Asian, African, West Indian, and Mediterranean descent.
Clitheroe Castle Museum is adjacent to the castle. The castle was listed as a Scheduled Monument on 10 April 1915 (and later, under the Ancient Monuments and Archaeological Areas Act 1979 law).It was Grade I listed on 19 May 1950.t has been suggested that Clitheroe Castle may have been first built before 1086 as there is reference to the  castellatu Rogerii pictaviensis  in the Domesday Book entry for nearby Barnoldswick. However, it is likely the passage refers to another castle.
It was owned by the Greville family, who became earls of Warwick in 1759, until 1978.From 1088, the castle traditionally belonged to the Earl of Warwick, and it served as a symbol of his power. The castle was taken in 1153 by Henry of Anjou, later King Henry II.