That way we can tell whether or not somebody has all the proper number of chromosomes, which is 46, and that way we can look at the X and the Y chromosomes and determine if it's a female or male.
Somebody might order a chromosome study and look at a karyotype if they were worried that a child might have an extra or missing bit of chromosome material. So one of the most common things we can see on karyotyping is an extra Chromosome 21, which is associated with Down syndrome.
We also get karyotypes when pregnant women choose to have testing on their unborn fetus, and the karyotype allows the providers to look at and count the chromosomes to determine whether or not the child is affected by having an extra chromosome. In some cases, a problem may occur to the cells growing in the lab dish.
Karyotype tests should be repeated to confirm that an abnormal chromosome problem is actually in the body of the person. Bacino CA, Lee B. Nelson Textbook of Pediatrics. Philadelphia, PA: Elsevier; chap Stein CK.
Applications of cytogenetics in modern pathology. St Louis, MO: Elsevier; chap The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.
Any duplication or distribution of the information contained herein is strictly prohibited. Your provider will insert a thin needle into your abdomen and withdraw a small amount of amniotic fluid.
Amniocentesis is usually done between week 15 and 20 of pregnancy. For CVS: You'll lie on your back on an exam table. Your provider will move an ultrasound device over your abdomen to check the position of your uterus, placenta, and baby. Your provider will collect cells from the placenta in one of two ways: either through your cervix with a thin tube called a catheter, or with a thin needle through your abdomen.
CVS is usually done between week 10 and 13 of pregnancy. For this test: You'll lie on your side or your stomach, depending on which bone will be used for testing. Most bone marrow tests are taken from the hip bone.
The site will be cleaned with an antiseptic. You will get an injection of a numbing solution. Once the area is numb, the health care provider will take the sample. For a bone marrow aspiration, which is usually performed first, the health care provider will insert a needle through the bone and pull out bone marrow fluid and cells.
You may feel a sharp but brief pain when the needle is inserted. For a bone marrow biopsy, the health care provider will use a special tool that twists into the bone to take out a sample of bone marrow tissue. You may feel some pressure on the site while the sample is being taken. Will I need to do anything to prepare for the test? You don't need any special preparation for karyotype testing. Are there any risks to the test? What do the results mean? Some disorders caused by chromosomal defects include: Down syndrome , a disorder that causes intellectual disabilities and developmental delays Edwards syndrome, a disorder that causes severe problems in the heart, lungs, and kidneys Turner syndrome , a disorder in girls that affects the development of female characteristics If you were tested because you have a certain type of cancer or blood disorder, your results can show whether or not your condition is caused by a chromosomal defect.
Is there anything else I need to know about a karyotype test? Washington D. Atlanta: American Cancer Society Inc. Amniocentesis; [updated Sep 2; cited Jun 22]; [about 2 screens]. Atlanta: U. C: American Association for Clinical Chemistry; c— Chromosome Analysis Karyotyping ; [updated Jun 22; cited Jun 22]; [about 2 screens].
Down Syndrome; [updated Feb 28; cited Jun 22]; [about 2 screens]. Mayo Foundation for Medical Education and Research; c— Bone marrow biopsy and aspiration: Overview; Jan 12 [cited Jun 22]; [about 4 screens].
Chronic myelogenous leukemia: Diagnosis and treatment; May 26 [cited Jun 22]; [about 5 screens]. Bone Marrow Examination; [cited Jun 22]; [about 2 screens].
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