The prevalence of cholangiocarcinoma in people with primary sclerosing cholangitis may be as high as 30%, based on autopsy studies.Multiple studies have documented a steady increase in the incidence of intrahepatic cholangiocarcinoma; increases have been seen in North America, Europe, Asia, and Australia. The reasons for the increasing occurrence of cholangiocarcinoma are unclear; improved diagnostic methods may be partially responsible, but the prevalence of potential risk factors for cholangiocarcinoma, such as HIV infection, has also been increasing during this time frame. References
External links

American Cancer Society Detailed Guide to Bile Duct Cancer. Patient information on extrahepatic bile duct tumors, from the National Cancer Institute. Cancer.Net: Bile Duct Cancer
Cholangiocarcinoma Foundation
World Cholangiocarcinoma Day
These developmental abnormalities include absence of the limb, failure of portions of the limb to separate (commonly fingers and toes), duplication of digits, or overgrowth or undergrowth of limbs. Genetics
Inheritance Pattern
The inheritance pattern for the Chromosome 9p deletion syndrome is inherited in an autosomal dominant inheritance pattern. This means that a single copy of the deletion is sufficient to cause the disease. Mutation
The mutation, which occurs in the form of a deletion of the short arm of chromosome 9, causes the cell to not express the gene products normally controlled by the genes within the chromosome 9 deletion. Genes Involved
The 9p deletion causes a loss of genes that would normally be there. Which genes are lost on the short arm of chromosome 9 dictates the symptoms that are present within the individual and the spectrum of disease severity. Most of the genes involved are associated with the development of tissues.There are many possible genes that can be deleted, but two particular genes that are proven to be involved in the emergence of the symptoms associated with Chromosome 9p deletion syndrome are DMRT1 and DMRT2. When DMRT1 and DMRT2 are deleted, genital malformations and mental retardation are evident although, the direct mechanisms as to how this occurs remains undefined. Location
Geneticists originally had the syndrome narrowed down to the short arm region of Chromosome 9. Now, the location of the deletion has recently been narrowed to 9p22.2-p23. Diagnosis
Diagnoses can occur at any age.