|
XXXXX syndrome (also called pentasomy X or 49,XXXXX) is a type of aneuploidy (an abnormal number of chromosomes) which results in the presence of three additional X chromosomes. The condition was first described in 1963. It is characterised by severe mental retardation, short stature and abnormalities to the head and face.〔 As these features can be seen in other conditions, karyotyping must be carried out to confirm diagnosis. There have been cases of XXXXX syndrome being misdiagnosed as Down syndrome.〔 It is an extremely rare condition with no more than 30 patients reported in medical literature.〔 The exact incidence is not known but it may be similar to the rate of 1 in 85,000 seen in males with 49, XXXXY syndrome. ==Signs and symptoms== The main characteristics of XXXXX syndrome are mental retardation, short stature and craniofacial abnormalities.〔 Other physical traits include the following: * Small head * Ear abnormalities〔 * Widely spaced eyes with upward slanting palpebral fissures and epicanthal folds 〔 * Short neck〔 * Broad nose with a depressed nasal bridge〔 * Hyperextension of the elbows〔〔 * Dental abnormalities and cleft palate〔〔 * Clinodactyly of the 5th finger〔〔 * Deformities of the feet〔〔 * Heart defects〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「49, XXXXX」の詳細全文を読む スポンサード リンク
|