Jacobsen syndrome

Jacobsen syndrome is a rare congenital chromosomal disorder caused by the loss of genetic material from the end of the long arm of chromosome 11, and for that reason it is also called 11q terminal deletion disorder. The deleted stretch may span roughly five to sixteen million base pairs, and the more DNA is missing, the more severe the symptoms tend to be. People with the syndrome typically have intellectual disability, delayed development, distinctive facial features and a range of physical problems, including heart defects. A large majority also have Paris-Trousseau syndrome, a bleeding disorder caused by dysfunctional platelets. The condition can be fatal, with children dying in early life from heart complications in some cases. It was first identified by the Danish geneticist Petrea Jacobsen in 1973, in a family with an unbalanced translocation between chromosomes 11 and 21. No cure exists, so care focuses on managing the heart, bleeding, developmental and behavioural problems.