novo deletion- this is a random event that occurred during the formation of the sperm or the egg or during the cell division in the embryonic stage, where genes from chromosome 11 get deleted. Imbalanced translocation- in this case, a parent with balanced translocation or other types of chromosomal rearrangement can pass on these genes to their children which further results in an imbalanced translocation. The affected children have deletions on chromosome 11 as well as some extra genetic material from another chromosome. Ring chromosome 11- in this case genetic material from both long and short arm of the chromosome get deleted, and the remaining part joins and forms a ring like structure. Here the affected person would have symptoms associated with both 11q and 11p deletion. Genetics If de novo deletion occurs then both the parents have normal chromosomes, and chances that another child will have the deletion decline. Very few cases have been found in which the deletion has been present in mosaic form (where some of the cells have deletion on chromosome 11 and some do not, and the symptoms are less severe) in one of the parents, which increases the risk of having another child with Jacobsen syndrome. When the child's chromosomal abnormality occurs due to one of the parents' balanced translocation, the chances of another child having the abnormality is high. Diagnosis Diagnosing Jacobsen syndrome can be difficult in some cases because it is a rare chromosomal disorder. There are a variety of tests that can be carried out, like karyotypes, cardiac echocardiograms, a renal sonogram, a platelet count, blood counts, a brain imaging study. Genetic testing can be carried out for diagnosis. Here chromosomes are stained to give a barcode like appearance and studied under the microscope, which reveals the broken and deleted genes. The condition can also be diagnosed early in the prenatal stage if there are any abnormalities seen in the ultrasound. A simple assessment of the symptoms can be done to diagnose the syndrome. A thorough physical examination could be carried out to assess the symptoms. Treatment There has been no treatment discovered for Jacobsen syndrome to date, but the symptoms can be treated. 56% of children with Jacobsen syndrome have congenital heart problems; to keep them in check, a baseline evaluation can be made by a paediatric cardiologist by carrying out an electrocardiogram or echocardiogram. Any problems that are found