XXX SYNDROME

Alternate names: Triple X syndrome, Triplo-X, Trisomy X, Metafemale, XXX aneuploidy

Overview: A metafemale is a woman who has an extra chromosome. The extent to which an individual is affected by the condition will depend on the ratio of abnormal XXX body cells she has in relation to the normal XX body cells.

Karyotype of an individual with Triple X syndrome

Characteristic/Phenotype: Triple X syndrome usually has only mild to no effects since afflicted females show no discernible difference to XX females. However, the most common indications of Triple X syndrome include:

• tall stature (taller than the average; the most common observable physical anomaly)
• behavioural problems (low self-esteem, personality and psychological problems, anxiety)
• learning disabilities (usually dyslexia and speech/language skills)
• clumsiness and poor coordination caused by delayed development of some motor skills
• wide set eyes and epicanthal folds (vertical skinfolds covering inner corners of the eyes)
• reduced muscle tone (hypotonia)
• ovarian failure and abnormalities although the patient can be fertile
• small head (microcephaly)
• curved pinky fingers (clinodactyly)

Symptoms vary from person to person, which depends on the proportion of XX and XXX cells (mosaicism).

At birth, afflicted females have lower birth weight and smaller head circumference along with EEG (electroencephalogram), urogenital and ophthalmological abnormalities. Most cases are not suspected after birth and many remain undiagnosed.

Frequency: 1 in 1000 female has an extra X chromosome

Causes: Occurs as a result of nondisjunction during meiosis. Random postzygotic nondisjunction can also occur in 20 percent of the cases. Most cases are not inherited although the risk increases with advanced maternal age.

Diagnosis: Triple X Syndrome can be diagnosed prenatally by amniocentesis or chorionic villi sampling. Postnatal diagnosis is typically done by a blood test and karyotyping

Treatment/Recommendations/Therapies: Patients diagnosed in the prenatal period should be monitored closely to employ intervention therapies in case of developmental delays. Genetic counselling is needed for the parents to be informed about what is known about the syndrome.

School age and adolescent patients should undergo psychological evaluation to identify problems in areas such as in the cognitive skills, language and social-emotional development in order to make a personalized learning program for the patient’s learning. 

Regular neuropsychological and linguistic testing using test batteries suited to the consecutive age groups must be employed to assess learning and determine if intervention strategies could be employed.

The developmental, behavioural, or educational difficulties are caused by linguistic, auditory and neurocognitive disorders which entails that awareness and understanding of the condition is required for parents, teachers, clinicians and other people in order not to augment the condition and not further aggravate it.

Despite all the tests and diagnostic procedures, it is important to treat the afflicted child as normal as possible and focus only on the problems of specific nature that were observed. For example if the child is having speech and language difficulties, parents can seek help from Speech/Language services.

Most triple X patients manifest psychotic disorders and paranoid symptoms. Low self-esteem has been reported in most patients in an Edinburgh study. There seemed to be some improvement in quality of life after leaving school. Therefore, triple X patients must be taken care in stable families and small intimate social groups.

Those afflicted with severe psychiatric illness may be given inpatient care and, in some cases neuroleptic (antipsychotic) treatment. Literature also proved the effective treatment using electro-convulsive therapy.

Patients should refer to support organizations for individual and family support.

Support Groups:

Contact Triple X Syndrome (Dutch)

http://www.triple-x-syndroom.nl/nederlandsefolder

References: 

Maarten, O, Schrander-Stumpel, C, Curfs, L. (2010) Triple X syndrome: A Review of the Literature. Retrieved March 12, 2013 from the URL: http://www.nature.com/ejhg/journal/v18/n3/full/ejhg2009109a.html

Tartaglia, N. et al. (2010). A Review of Trisomy X (47, XXX). Retrieved March 12, 2013 from the URL: http://www.ojrd.com/content/5/1/8/abstract

Photo from:
http://www.jhrsonline.org/articles/2011/4/3/images/JHumReprodSci_2011_4_3_153_92292_u1.jpg