What is the definition of Chromosome 15q Duplication?
Chromosome 15q duplication is a chromosome abnormality that occurs when an extra (duplicate) copy of the genetic material located on the long arm (q) of chromosome 15 is present in each cell. The severity of the condition and the associated signs and symptoms vary based on the size and location of the duplication and which genes are involved. Common features shared by many people with this duplication include developmental delay; intellectual disability; hypotonia (low muscle tone); seizures; high and/or cleft palate (roof of the mouth); scoliosis; slow growth; communication difficulties; behavioral problems; and distinctive facial features. Most cases are not inherited, although affected people can pass the duplication on to their children. Treatment is based on the signs and symptoms present in each person.
What are the alternative names for Chromosome 15q Duplication?
- Duplication 15q
- Trisomy 15q
- 15q duplication
- 15q trisomy
- Partial trisomy 15q
What are the causes for Chromosome 15q Duplication?
People with chromosome 15q duplication have an extra (duplicate) copy of the genetic material located on the long arm (q) of chromosome 15 in each cell. The features associated with the condition vary significantly from person to person depending on the size and location of the duplication and which genes are involved. In many cases, this duplication occurs sporadically as a random event when the egg or the sperm is made. There is nothing that a person can do to cause or prevent this duplication from happening.
What are the symptoms for Chromosome 15q Duplication?
The signs and symptoms of chromosome 15q duplication vary significantly from person to person, depending upon the size and location of the duplication and which genes are involved. Features that may be present in a person with a chromosome 15q duplication include:
- Developmental delay
- Intellectual disability
- Hypotonia (low muscle tone)
- High and/or cleft palate
- Distinctive facial features
- Genital abnormalities
- Feeding difficulties
- Slow growth
- Communication difficulties
- Behavioral and/or emotional problems
- Autism spectrum disorder
- Abnormalities of the heart, kidney, and/or other organs
What are the current treatments for Chromosome 15q Duplication?
Because chromosome 15q duplication affects many different systems of the body, medical management is often provided by a team of doctors and other healthcare professionals. Treatment for this duplication varies based on the signs and symptoms present in each person. For example, children with delayed motor milestones (i.e. walking) may be referred for physical or occupational therapy. Speech therapy may be recommended for children with delayed speech. Certain medications may be prescribed to treat seizures. Special education services are often necessary for children with intellectual disability. Surgery may be required to treat certain physical abnormalities such as cleft palate or congenital heart defects, if present.
Please speak to your healthcare provider if you have any questions about your personal medical management plan.
What is the outlook (prognosis) for Chromosome 15q Duplication?
The long-term outlook (prognosis) for people with chromosome 15q duplication varies from person to person. The severity of the condition and the associated signs and symptoms largely depend on the size and location of the duplication and the genes involved.
How is Chromosome 15q Duplication diagnosed?
There are several different specialized tests that can be used to diagnose a chromosome 15q duplication. These include:
- Karyotype - a karyotype is a laboratory test that produces an image of a person's chromosomes. This test can be used to diagnose large duplications.
- FISH - a laboratory technique that is used to detect and locate a specific DNA sequence on a chromosome. During FISH, a chromosome is exposed to a small DNA sequence called a probe that has a fluorescent molecule attached to it. The probe sequence binds to its corresponding sequence on the chromosome. This test can be used in combination with karyotyping for duplications that are too small to be seen on karyotype, alone. However, FISH is only useful if the person ordering the test suspects there is a duplication of a specific region of 15q.
- Array CGH - a technology that detects duplications that are too small to be seen on karyotype.
Is Chromosome 15q Duplication an inherited disorder?
Many cases of chromosome 15q duplication occur sporadically as a random event during the formation of the egg or sperm. In this case, a person would have no family history of the condition but could pass the duplication on to children.
Occasionally, this duplication is passed down from parent to child. However, the symptoms and severity can vary significantly between family members and in some cases, the parent may have no obvious features of the condition.