16p11.2 duplication syndrome is a rare genetic disorder where a part of the sixteenth chromosome is duplicated. This means instead of two copies of the genes in this piece, three copies are found in the cells. The duplicated material is from the short (p) arm of the chromosome. The duplication may be caused by a random mistake or mutation (de novo) when the egg or sperm is being made or may be inherited from a parent.
The effects of the syndrome can vary based on the size of the duplication and the specific genes involved. Common symptoms include developmental delays, speech delays, and difficulties with social interactions. Many affected individuals may seem similar to children with autism. Individuals may also experience learning difficulties and are often diagnosed with ADHD (attention-deficit hyperactivity disorder). Other common symptoms include mental health problems such as anxiety, depression, bipolar disorder, and schizophrenia. There are also cases where the individual may have no noticeable symptoms.
Physical symptoms may vary based on the size and area involved in the duplication. Many individuals with 16p11.2 duplications have a small head (microcephaly) in relation to their body. Individuals are often underweight, but may become overweight as they age. Other symptoms include a variety of birth defects, which range from mild to severe and affect different organs. Seizures may develop but usually can be controlled with medication.
Although there is no cure for 16p11.2 duplication syndrome, there are many resources available to help manage the condition and treat birth defects. Doctors may seek help from various therapists and community services to help care for and support families affected by this condition. Genetic counselors and support groups are great resources of information and offer a way to become connected with other families with the same condition.