Trisomy X is a caused by the presence of an extra X chromosome in females (47,XXX instead of 46,XX). This is also the most common female chromosomal abnormality, occurring in approximately 1 in 1,000 female births.
Other abnormalities of chromosome number include: female tetrasomy X (quadruple X, or 48, XXXX) a rare chromosomal disorder and male Klinefelter syndrome, the presence of an additional X chromosome (47, XXY or XXY).
- Alternative names: Triplo X syndrome, Trisomy X, 47,XXX, XXX syndrome
- Genetic Links: Introduction | Genetic risk maternal age | Trisomy 21 | Trisomy 18 | Trisomy X | Fragile X | Williams | Philadelphia chromosome | Prenatal Diagnosis | Neonatal Diagnosis | International Classification of Diseases | Molecular Development - Genetics| Genital System - Abnormalities
Some Recent Findings
The most common prenatal diagnosis is by either amniocentesis or chorionic villi sampling.
|Feature||Estimated frequency based on current available data|
|Tall stature >75th percentile||80 - 89 %|
|Epicanthal folds||32 - 46 %|
|Clinodactyly||42 - 65 %|
|Hypotonia in infancy||55 - 71 %|
|Genitourinary malformations||5 - 16 %|
|Seizure disorder||11 - 15 %|
|Intention tremor||6 - 20 %|
|Congenital hip dysplasia||2 - 12 %|
|Constipation/Abdominal pains||12 - 45 %|
|Premature ovarian failure||unknown|
Table data from Tartaglia NR, etal., 2010
- ↑ 1.0 1.1 Nicole R Tartaglia, Susan Howell, Ashley Sutherland, Rebecca Wilson, Lennie Wilson A review of trisomy X (47,XXX). Orphanet J Rare Dis: 2010, 5();8 PMID:20459843
- ↑ Raija E Lähdesmäki, Lassi J Alvesalo Root length in the permanent teeth of women with an additional X chromosome (47,XXX females). Acta Odontol. Scand.: 2010, 68(4);223-7 PMID:20568965
Nicole R Tartaglia, Susan Howell, Ashley Sutherland, Rebecca Wilson, Lennie Wilson A review of trisomy X (47,XXX). Orphanet J Rare Dis: 2010, 5();8 PMID:20459843
Jeannie Visootsak, John M Graham Klinefelter syndrome and other sex chromosomal aneuploidies. Orphanet J Rare Dis: 2006, 1();42 PMID:17062147
Aniel Jessica Leticia Brambila-Tapia, Horacio Rivera, Herbert García-Castillo, Maria Guadalupe Domínguez-Quezada, Ingrid Patricia Dávalos-Rodríguez 47,XXX/45,X/46,XX mosaicism in a patient with Turner phenotype and spontaneous puberal development. Fertil. Steril.: 2009, 92(5);1747.e5-7 PMID:19732877
T Lester, M de Alwis, P A Clark, A M Jones, F Katz, R J Levinsky, C Kinnon Trisomy X in a female member of a family with X linked severe combined immunodeficiency: implications for carrier diagnosis. J. Med. Genet.: 1994, 31(9);717-20 PMID:7815443
K Tennes, M Puck, K Bryant, W Frankenburg, A Robinson A developmental study of girls with trisomy X. Am. J. Hum. Genet.: 1975, 27(1);71-80 PMID:1155452
A W JOHNSTON, M A FERGUSON-SMITH, S D HANDMAKER, H W JONES, G S JONES The triple-X syndrome. Clinical, pathological, and chromosomal studies in three mentally retarded cases. Br Med J: 1961, 2(5259);1046-52 PMID:14452136
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