Chromosome 15q duplication syndrome. 15q+ syndrome. Trisomy 15q.
Incidence
Very rare syndrome. Sporadic.
Clinical Characteristics
Chromosome 15, Distal Trisomy 15q is an extremely rare chromosomal disorder in which the end (distal) portion of the long arm (q) of the 15th chromosome (15q) appears three times (trisomy) rather than twice in cells of the body. The disorder is characterized by growth delays before and/or after birth (prenatal and/or postnatal growth retardation); mental retardation; and/or distinctive malformations of the head and facial (craniofacial) area. Additional abnormalities typically include an unusually short neck; malformations of the fingers and/or toes; abnormal sideways curvature of the spine (scoliosis) and/or other skeletal malformations; genital abnormalities, particularly in affected males; and/or, in some cases, heart (cardiac) defects. The range and severity of symptoms and physical findings may vary from case to case, depending upon the length and location of the duplicated portion of chromosome 15q. In most cases, Chromosome 15, Distal Trisomy 15q is due to a chromosomal balanced translocation in one of the parents. Some cases have symptoms which are similar to those in Prader-Willi and Angelman syndromes but most exhibit a wide spectrum of manifestations which range from asymptomatic cases to variable combinations of skeletal, neurological, gastrointestinal, psychological, and other abnormalities in association with developmental delay. Phenotypic expression and degree of severity are related to the length of the duplicated segment. Translocation was reported in nearly half of the patients and de novo duplication was observed in a large number of other cases.
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
Karyotype. Chromosome 15q duplication syndrome.