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TURNER SYNDROME
Turner syndrome only affects females. It is also called monosomy X, and it results from having only one copy of chromosome X.
Genetically, Turner syndrome can often arise from nondisjunction errors occurring in meiosis. Nondisjunction of the sex chromosomes during meiosis I and II can result in gametes that do not have any sex chromosomes. When such a sex-chromosome “empty” gamete combines with an X chromosome, this results in an embryo with an “XO” genotype.
Monosomy resulting from
- nondisjuction (XO)
- mosaicism (XX, XO; XY, XO)
- only monosomy not aborted in utero
- no Barr bodies
PHYSICAL EXAMINATION
• SHORT STATURE
• WEBBED NECK
• SHIELD CHEST
• WRIST AND ANKLE EDEMA
• CUBITUS VALGUS
• PTOSIS, HYPERTELORISM
• RETROGNATHISM
Pathogenesis:
Decreased estradiol, increased FSH, LH
Normal GH, IGF-1 levels
CLINICAL FEATURES
Female patients with Turner syndrome have several distinguishing physical features including short stature and a broad chest with widely spaced nipples. Those with Turner syndrome are often born with multiple congenital problems. These can include: Cardiovascular problems - bicuspid aortic valve and aortic coarctation.
Lymphatic system, the organ system that drains lymphatic fluid flow. These lymphatic problems can present as a webbed neck (extra skin folds on the neck) or cystic hygroma (fluid-filled sac from blocked lymphatics in the neck). Endocrine abnormalities affecting their ovarian status (infertility).
Renal- Horseshoe kidney Increased risk of dysgerminoma ovarian tumor.
People with Turner syndrome are born with defective, nonfunctional, or less functional ovaries. Their ovaries are replaced with functionless fibrous tissue, and as a result, these patients do not produce enough estrogen. The ovaries stop functioning normally at a young age—termed premature ovarian failure—due to a lack of sufficient estrogen, and the eggs contained in the ovary are not released correctly. These are called streak ovaries.
Turner syndrome is the most common cause of primary amenorrhea. Individuals with Turner syndrome often have issues with fertility due to ovarian dysgenesis (abnormal development of the ovaries) and premature ovarian failure. In some cases, pregnancy is possible with in vitro fertilization (IVF) and exogenous estradiol-17B and progesterone treatments.
DIAGNOSIS
