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Turnner syndrome


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Turnner syndrome

  1. 1. TURNER SYNDROME (TS) OTHER NAMES Bonnevie-Ullrich-Turner syndrome Gonadal dysgenesis Ovarian dysgenesis Turner's syndrome Ullrich-Turner syndrome XO syndrome, monosomyX INTRODUCTION Turner syndrome (TS) was first described in 1938, when Dr. Henry Turner syndrome (TS) is a chromosomal disorder that affects females and is caused by a complete or partial loss of the second sex-determining chromosome. The syndrome is typically characterized by short stature, ovarian insufficiency, and malformations in organ systems that could include cardiac defects (particularly coarctation of the aorta and bicuspid aortic valve), lymphedema (especially nuchal and over the dorsum of the hands and feet), short 4th metacarpals, and genitourinary malformations (such as horseshoekidney). Some affected individuals are phenotypically normal females with only short stature. Others can have life- threatening cardiovascular, hormonal, and lymphatic anomalies or manifestations, such as short stature, pubertal delay, and sterility, which impart significant psycho- emotional burden and a higher risk for co-morbidities. INCIDENCE TS is present in approximately 1 in 2000 to 2500 live female births worldwide. Prevalence is greater if pregnancies that do not survive to term are taken into account. Clinical Classification Types of chromosomalanomalies associated with TS 1. 45, X (monosomy X) is found in approximately 45% of live births with TS; these patients should be evaluated for presence of Y chromosomematerial. 2. 45, X mosaicism is a mosaic chromosomal complement (e.g., 45,X/46,XX) detectable in 20-30% of all patients with TS. 3. X chromosomeanomalies:
  2. 2. CAUSES About half of women with TS are completely missing the second sex chromosome; in the other half, it may be partially missing or rearranged. Mosaic TS occurs when only some of the individual’s cells lack the second normal sex chromosome. The severity of the phenotype is related to the absence or presence of a second sex chromosome. Full monosomy(45,X or 45,XO) typically is the most severe form and mosaic TS is typically the mildest form. The SHOX gene plays a large role in determining height and bone growth. It is located on the X chromosomein both men and women. When all or part of an X chromosomeis missing, so is the SHOX gene. This accounts for the short stature commonly associated with Turner syndrome. CLINICAL FEATURES  Unexplained growth failure  Low-set ears  Micrognathia  Epicanthal folds  Nuchal redundancy, cystic hygroma  Widely spaced nipples, perhaps with shield chest and pectus excavatum  Cystic hygromalymphedema sequence (edema of hands or feet, webbed neck, low hairline, hyperconvex and hypoplastic nails)  Cardiac anomalies, such as bicuspid aortic valve, coarctation of aorta  Cubitus valgus  Multiple pigmented nevi  Short fourth metacarpal bones  Madelung deformity
  3. 3.  Hearing loss  Elevated FSH In childhood and adolescence  Short stature (in nearly 100%)  Chronic otitis media  Scoliosis  Hyperconvex, narrow fingernails; thin, mildly dysplastic toenails  Pubertal delay  Ovarian deficiency DIAGNOSIS I. History collection II. Physical examination III. Sensory Testing An audiologist should perform a hearing evaluation at diagnosis and every 3-5 years thereafter. If there is a history of otitis media or hearing loss, evaluations are usually performed annually. TS is associated with red-green color blindness (10%), hyperopia (35%), and strabismus (25%) with risk of amblyopia. Girls with TS should be evaluated by a pediatric ophthalmologist by 12-18 months of age or earlier if clinically indicated. If initial evaluation is normal, the medical home provider should conductannual routine vision screening. IV. Laboratory Testing a) Assess thyroid function with a TSH and T4. b) Screen for celiac disease with a tissue transglutaminase iga (TTG) and total serum iga. c) Perform hepatic function panel, GGT, hba1c with or without fasting plasma glucose, fasting lipid panel. d) 25-hydroxyvitamin D V. Echocardiography VI. Genetic Testing TREATMENT
  4. 4. a) Growth hormone therapy to achieve greater height, b) Estrogen replacement therapy to mimic natural estrogen. c) Reproductive technologies have also been used to help women with Turner syndrome become pregnant if they desire.