48, XXXX 3823832 221332101 2008-06-24T01:45:30Z 118.67.13.53 /* Symptoms */ {{Infobox_Disease | Name = XXXX syndrome | Image = | Caption = | DiseasesDB = 32550 | ICD10 = {{ICD10|Q|97|1|q|90}} | ICD9 = | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = }} '''XXXX syndrome''' (also called '''tetrasomy X''', '''quadruple X''', or '''48, XXXX''') is a rare [[Chromosome abnormalities|chromosomal disorder]] caused by the presence of four [[X chromosome]]s instead of two X chromosomes, which are normally found in females. This condition occurs only in females, as there are no Y chromosomes present. Tetrasomy X was first described in [[1961]], and since then approximately 100 cases have been reported worldwide. Approximately 60 females have been described in medical literature with this condition{{Fact|date=August 2007}}. ==Causes and Diagnosis== Tetrasomy X is a [[aneuploidy|chromosomal aneuploidy]], meaning it arises from a defect in [[meiosis]]. This can occur when homologous X chromosomes fail to separate in the formation of the egg or sperm. Tetrasomy X is usually suspected based on symptoms present in the individual and is confirmed via [[karyotype|karyotyping]], which reveals the extra X chromosomes. ==Symptoms== Symptoms of tetrasomy X are highly variable, ranging from relatively mild to severe. Physically, tetrasomy X patients tend to have distinctive facial features such as [[epicanthal fold]]s, flat nasal bridges, upslanting palpebral fissures, midface [[hypoplasia]], small mouths, [[cleft palate|cleft or high arched palates]], delayed or absent teeth, or enamel defects. The majority have also been reported as being longer and taller. Many also show joint and muscle tone abnormalities, including [[hypotonia]] and joint looseness in the hips. Skeletal problems may also be present, including abnormal curvatures of the spine. An informal study conducted by [http://www.genealogysource.com/tetra_x/ Tetrasomy & Pentasomy X Syndrome Information and Support] found that 10% of girls had joint laxity in the hips and 20% had joint limitations in a sample size of 20 tetrasomy and pentasomy patients. In terms of intelligence, clinical findings suggest that [[Intelligence quotient|IQ]] decreases 10 to 15 points per extra X chromosome. Consequently, the average IQ scores of tetrasomy X patients are between 60 and 70.{{Fact|date=May 2008}} Developmentally, tetrasomy X patients frequently show mild delays in the areas of speech development and articulation, language expression and understanding, and reading skills. Delays in motor development are also present, with walking ages ranging from 16 months to 4.5 years. About 50% of patients undergo [[puberty]] normally, whereas the other 50% experiences no puberty, partial puberty without secondary sexual characteristics, or complete puberty with menstrual irregularities and/or early menopause (possibly as early as the teens). Medical literature reports four tetra-X pregnancies, two healthy, one with [[trisomy 21]], one stillborn with [[omphalocele]]. In terms of internal organ systems, tetrasomy X patients may have abnormal vision, hearing, circulatory systems, kidneys, or nervous systems. Disorders of the eye include [[myopia]], [[nystagmus]], [[coloboma]], [[microphthalmus]], or [[optic nerve hypoplasia]]. In terms of hearing, patients are more prone to [[ear infection]]s, sound blockage, or nerve abnormalities. Several cardiac defects have also been reported, including [[septal defect|ventricular/atrial septal defects]], [[atresia]], [[hypoplastic right heart syndrome]], [[patent ductus arteriosus]], and conotruncal or valvular cardiac defects. Tetrasomy X patients also appear to be more prone to seizure activity, although there is no documented abnormalities in brain function or structure when analyzed using an [[EEG]] or [[MRI]]. ==Treatment and Prognosis== The general prognosis for girls with tetrasomy X is relatively good. Due to the variability of symptoms, some tetrasomy X girls are able to function normally, whereas others will need medical attention throughout their lives. Traditionally, treatment for tetrasomy X has been management of the symptoms and support for learning. Most girls are placed on estrogen treatment to induce breast development, arrest longitudinal growth, and stimulate bone formation to prevent osteoporosis. Speech, occupational, and physical therapy may also be needed depending on the severity of the symptoms. ==See also== * [[Triple X syndrome]] * [[XXXXX syndrome]] ==References== * {{cite journal | author=Linden MG, Bender BG, Robinson A | title=Sex chromosome tetrasomy and pentasomy | journal=Pediatrics | year=1995 | pages=672–82 | volume=96 | issue=4 Pt 1 | pmid=7567329}} * {{cite journal | author=Rooman RP, Van Driessche K, Du Caju MV | title=Growth and ovarian function in girls with 48,XXXX karyotype--patient report and review of the literature. | journal=J Pediatr Endocrinol Metab. | year=2002 | pages=1051–5 | volume=15 | issue=7 | pmid=12199336}} ==External links== * [http://www.genealogysource.com/tetra_x/ Tetrasomy & Pentasomy X Syndrome Information and Support] * [http://www.madisonsfoundation.org Rare Pediatric Disease Database] {{Chromosomal abnormalities}} [[Category:Genetic disorders]] [[Category:Genetics]] [[Category:Rare diseases]] [[pl:Tetrasomia chromosomu X]]