Rareshare would like to acknowledge Dr. Michael Joseph O’Grady, Department of Paediatrics, Midland Regional Hospital, Co. Westmeath, Ireland; and Professor Anne Slavotinek, Professor of Clinical Pediatrics, University of California, USA for reviewing this content. We would also like to thank Usman Kamran for compiling this information.

15q26 deletions are extremely rare, with a prevalence of less than 1 in 1,000,000.

Most 15q26 mutations are regarded as de novo mutations, meaning that they arise spontaneously. They are generally caused by a mistake in the formation of the sperm or egg cells, or in the early days following fertilization. De novo mutations are not inherited and there is no family history of the disorder. Currently, there are no environmental factors known to cause these changes.

The symptoms and how severe the disorder will be can vary among affected children. Children in general display symptoms involving, to varying extents, childhood developmental delays. These may involve delays in communication, the development of language, and difficulty learning. Delays in developing motor skills including sitting up or crawling also occur.

In many cases, infants require additional support when feeding. They are observed to have bendy joints, and their facial features are sometimes distinctive and different from those of the rest of the family. In some cases, an observable defect in the diaphragm, known as a diaphragmatic hernia, has been observed. The diaphragm is the muscle that separates the chest cavity from the abdominal cavity. A hernia means that there is a hole in the diaphragm, which can allow organs from the abdominal cavity to push into the chest cavity. Heart problems have also been found in babies, involving an unusual formation, narrowing, or blockages of valves
regulating cardiac blood flow.

Babies with 15q26 deletions have been observed to be very small at birth and have continued growth delays. Babies with 15q26.1 and 15q26.2 deletions are more prone to have seizures.

Sequencing analysis is currently the primary means to detect this deletion. If the deletion is large enough it can be also be detected by looking at a DNA preparation under the microscope.

See above.

There are currently no known cures for this disease. Some studies have reported a limited benefit with growth hormone therapy for some children with 15q26.3 deletions.

Presently, symptoms of the condition are treated as they present themselves.

There have been varied outcomes for patients with 15q26 deletions. Of the 24 reported cases studied by Unique, three were unable to overcome childhood heart and lung complications. 14 are reported to be healthy and rarely ill, whilst the remainder suffer from occasional health concerns.

https://www.omim.org/clinicalSynopsis/612626

https://www.rarechromo.org/information/Chromosome%2015/15q%20deletions%20FTNW.pdf

https://www.rarechromo.org/information/Chromosome%2015/15q26%20deletions%20FTNW.pdf

https://www.researchgate.net/publication/275668472_Recombinant_Human_Growth_Hormone_Therapy_in_Children_with_Chromosome_15q26_Deletion

http://www.orpha.net/consor/cgi-bin/Disease_Search.php?lng=EN&data_id=1737&Disease_Disease_Search_diseaseGroup=15q26&Disease_Disease_Search_diseaseType=Pat&Disease%28s%29/group%20of%20diseases=Distal-monosomy-15q&title=Distal-monosomy-15q&search=Disease_Search