What is the definition of Chromosome 4q Duplication?
Chromosome 4q duplication is a chromosome abnormality characterized by an extra copy (duplication) of genetic material on the long arm (q) of chromosome 4. The severity and specific symptoms depend on the size and location of the duplication, and which genes are involved. Features that have been described in some people with chromosome 4q duplication include developmental delay, intellectual disability, behavioral problems, birth defects, and distinctive facial features. Most cases are inherited from an unaffected parent with a chromosomal rearrangement called a balanced translocation. Some cases are not inherited and occur sporadically. Treatment is based on the signs and symptoms present in each person.
What are the alternative names for Chromosome 4q Duplication?
- Duplication 4q
- Trisomy 4q
- 4q duplication
- 4q trisomy
- Partial trisomy 4q
What are the symptoms for Chromosome 4q Duplication?
The signs and symptoms associated with having a chromosome 4q duplication may depend on the size and location of the duplication; this affects which genes are involved. Since few cases of 4q duplication have been described in the literature, it is difficult to predict severity or the specific features that a person will have.
Someone with a small duplication may be very mildly affected and have no developmental delays. Others, even within the same family, may have varying degrees of developmental delay, any of several types of birth defects, and/or distinctive facial features.
While very few cases have been described, it seems that those with a very small duplication of material close to the middle of the chromosome (called a proximal duplication) are usually healthy with developmental delay and/or learning difficulties. Larger proximal duplications may be associated with heart or kidney problems.
When the duplication involves material closer to the tip of the chromosome (called a distal duplication), it may be associated with thumb and kidney abnormalities, developmental delay, and distinctive facial features.
If a chromosome 4q duplication occurs with another chromosome abnormality (such as a deletion of part of another chromosome), the severity and features in an affected person may differ and will depend on the effects of the other chromosome abnormality as well.
We encourage you to view Unique's guide for people and families with a chromosome 4q duplication. The information they provide is drawn from what is known about 43 people with a chromosome 4q duplication.
What is the outlook (prognosis) for Chromosome 4q Duplication?
The long-term outlook (prognosis) for people with a chromosome 4q duplication depends on the size and location of the duplication. This affects which specific genes are involved, and how many genes are duplicated. Some people with a 4q duplication may be born healthy and develop well, while others may be born with any of several types of birth defects that can lead to severe complications. Therefore, it is not possible to predict how one person will be affected. Additionally, people with the same 4q duplication (the same location and size) may be affected very differently - even within the same family.
People with questions about prognosis for themselves or family members are encouraged to speak with their doctors about how their signs and symptoms may affect their health and quality of life.