Jacobsen Syndrome is due to either a deletion of part of chromosome 11 (11q) or a chromosome 11 monosomy.
The loss of gene 11q24.1 results in this disorder. This is usually not due to inheritance (although this is possible through
a parent with a translocation that is balanced) but to a deletion in the gamete.
Those with Jacobsen Syndrome may exibit a small nose with a wide nasal bridge and upturned nostils, eyes that
are far apart, small head, small chin, thin upper lip, lower ears, and toes of a clawlike shape. They also tend to exhibit
a mental retardation, or mental developmental delay. Those with Jacobsen Syndrome tend to be smaller people than
others, and have a low platelet count. Other defects vary from person to person. Congenital heart disease may be present
in children, as well as blood disorders. Other abnormalities include kidney defects, undescended testes, and gastrointestinal
problems. A quarter of those with Jacobsen Syndrome die before they are two years old.
A diagnosis of Jacobsen Syndrome can be obtained through a chromosome analysis blood test of an infant who
appears to have the symptoms, or through amniocentesis.
Few treatments exist. Specialists are often consulted for the varying problems caused by Jacobsen Syndrome. Standard
tests to determine who should be consulted include a karyotype, blood count, hearing and vision tests, and a platelet count.
