NeurometPlus

Incidence

Triplo X Syndrome results from errors during the division of reproductive cells in one of the parents. Often clinically unsuspected.

Clinical Characteristics

A rare chromosomal aberration characterized by the presence of three X (female) chromosomes. The condition does not exhibit a distinctive phenotype and majority of the affected females are physically and mentally normal. Abnormalities are infrequent and do not occur with any regularity--they include hypertelorism, epicanthal folds, depressed nasal bridge, kyphosis and variable other anomalies. Delay in growth and mental development, when present, is usually mild. Occasionally associated with Prader-Willi syndrome. No specific pattern of symptoms and malformations (phenotype) has been found to be associated with this abnormal chromosomal make-up (i.e., 47,XXX karyotype). Many affected females appear to have no or very few associated symptoms, while others may have various abnormalities. However, investigators indicate that Triplo X Syndrome is a relatively common cause of learning difficulties, particularly language-based disabilities (e.g., dyslexia), in females. Evidence suggests that affected females typically have normal intelligence with IQs that tend to be lower than that of their brothers and sisters (siblings). Mental retardation rarely occurs. Infants and children with Triplo X Syndrome may tend to have delayed acquisition of certain motor skills and delayed language and speech development.

Precipitants

None

Provocation Tests

None

Diagnostic Procedures

Karyotype. Trisomy X.