Chromosome 3q duplication syndrome. 3q+ syndrome. Trisomy 3q syndrome.
Incidence
It is a rare chromosomal disorder. Duplication of the long arm of chromosome 3 may range from 3q25qter to the entire long segment. About 25% represent de novo duplication.
Clinical Characteristics
Chromosome 3, Trisomy 3q is a rare chromosomal disorder in which a portion of the 3rd chromosome appears three times (trisomy) rather than twice in cells of the body. Associated symptoms and findings may be variable, depending upon the specific length and location of the duplicated (trisomic) portion of chromosome 3. However, many affected infants and children have developmental delays, mental retardation, and characteristic abnormalities of the head and facial (craniofacial) area, resulting in a distinctive facial appearance. Such craniofacial abnormalities may include a relatively short head (brachycephaly), widely spaced eyes (ocular hypertelorism), upwardly slanting eyelid folds (palpebral fissures), and a small nose with upturned nostrils (anteverted nares). Affected infants and children also tend to have long eyelashes; arched, bushy, well-defined eyebrows that grow together across the base of the nose (synophrys); an unusually low hairline on the forehead and the back of the neck; and generalized excessive hair growth (hirsutism). Chromosome 3, Trisomy 3q2 may also be characterized by eye (ocular) abnormalities, limb defects, structural heart malformations (congenital heart defects), or other physical features. Duplication of the long arm of chromosome 3 with psychomotor retardation, characteristic facies, congenital heart anomalies, abnormal dermatoglyphic patterns, skeletal defects, and other abnormalities. The syndrome was first reported as familial de Lange syndrome with chromosomal abnormalities. Manifestations of dup(3q) are similar to those in de Lange syndrome. Intrauterine growth retardation, prominent philtrum, proximally placed thumbs, oligodactyly, and phocomelia are more frequent in de Lange syndrome, whereas craniosynostosis, cleft palate, and urinary tract anomalies are more common in dup(3q).
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
Karyotype. Chromosome 3, Trisomy 3q is a rare chromosomal disorder in which a portion of the 3rd chromosome appears three times (trisomy) rather than twice in cells of the body.