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Chorionic villus sampling (CVS), sometimes called "chorionic ''villous'' sampling" (as "villous" is the adjectival form of the word "villus"),〔A PubMed search yields 168 papers using ''chorionic villous'' as of June 15, 2011.〕 is a form of prenatal diagnosis to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus (placental tissue) and testing it for chromosomal abnormalities, usually with FISH or PCR. CVS usually takes place at 10–12 weeks' gestation, earlier than amniocentesis or percutaneous umbilical cord blood sampling. It is the preferred technique before 15 weeks. CVS was performed for the first time by Italian biologist Giuseppe Simoni, scientific director of Biocell Center, in 1983. Use as early as 8 weeks in special circumstances has been described. It can be performed in a transcervical or transabdominal manner. Although this procedure is mostly associated with testing for Down Syndrome, overall, CVS can detect more than 200 disorders. ==Indications== Possible reasons for having a CVS can include: *Abnormal first trimester screen results *Increased nuchal translucency or other abnormal ultrasound findings *Family history of a chromosomal abnormality or other genetic disorder *Parents are known carriers for a genetic disorder * Advanced maternal age (maternal age above 35). AMA is associated with increase risk of Down's syndrome and at age 35, risk is 1:400.〔(Incidence of Down syndrome | Pregnancy Signs Blog )〕 Screening test are usually carried out first before deciding if CVS should be done. 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「chorionic villus sampling」の詳細全文を読む スポンサード リンク
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