Category:Genetic Testing
From Holoprosencephaly
Prenatal Genetic testing
Genetic testing or counseling can help parents who have a family history of a neurological disease determine if they are carrying one of the known genes that cause the disorder or find out if their child is affected. Genetic testing can identify many neurological disorders, including spina bifida, in utero (while the child is inside the mother’s womb). Genetic tests include the following:
Amniocentesis, usually done at 14-16 weeks of pregnancy, tests a sample of the amniotic fluid in the womb for genetic defects (the fluid and the fetus have the same DNA). Under local anesthesia, a thin needle is inserted through the woman’s abdomen and into the womb. About 20 milliliters of fluid (roughly 4 teaspoons) is withdrawn and sent to a lab for evaluation. Test results often take 1-2 weeks.
Chorionic villus sampling, or CVS, is performed by removing and testing a very small sample of the placenta during early pregnancy. The sample, which contains the same DNA as the fetus, is removed by catheter or fine needle inserted through the cervix or by a fine needle inserted through the abdomen. It is tested for genetic abnormalities and results are usually available within 2 weeks. CVS should not be performed after the tenth week of pregnancy. Uterine ultrasound is performed using a surface probe with gel. This noninvasive test can suggest the diagnosis of conditions such as chromosomal disorders
