Chromosome 3q duplication

Chromosome 3q duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the long arm (q) of chromosome 3. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved. Features that may be present in a person with a chromosome 3q duplication include distinctive facial features, hirsutism (excessive hair growth in women), small head size (microcephaly), intellectual disability, slowed growth, and abnormalities of the hands, feet, genitourinary system, kidneys, and/or heart. Various other neurologic abnormalities or birth defects affecting other parts of the body may also occur. About one third of babies with chromosome 3q duplication do not survive past the first year of life, often due to heart defects or infections.

Chromosome 3q duplication can be de novo (not inherited and occurring for the first time), or inherited from a parent with a chromosomal rearrangement such as a balanced translocation. In most cases, it occurs as part of an unbalanced translocation, which means that abnormalities of other chromosomes are also present. Treatment is based on the signs and symptoms present in each person.