核型分析

定义

核型分析 is a test to examine chromosomes in a sample of cells. This test can help identify genetic problems as the cause of a disorder or disease.

选择的名字

染色体分析

How the Test is Performed

The test can be performed on almost any tissue, including:

• 羊水
• 血
• 骨髓
• Tissue from the organ that develops during pregnancy to feed a growing baby (placenta)

To test amniotic fluid, an 羊膜穿刺术 完成.

A 骨髓活检 is needed to take a sample of bone marrow.

The sample is placed into a special dish or tube and allowed to grow in the laboratory. Cells are later taken from the new sample and stained. The laboratory specialist uses a microscope to examine the size, 形状, and number of chromosomes in the cell sample. The stained sample is photographed to show the arrangement of the chromosomes. This is called a karyotype.

Certain problems can be identified through the number or arrangement of the chromosomes. Chromosomes contain thousands of genes that are stored in DNA, the basic genetic material.

How to Prepare for the Test

Follow the health care provider's instructions on how to prepare for the test.

How the Test will Feel

How the test will feel depends on whether the sample procedure is having blood drawn (静脉穿刺), 羊膜穿刺术, or 骨髓活检.

Why the Test is Performed

这个测试可以:

• Count the number of chromosomes
• Look for structural changes in chromosomes

This test may be done:

• On a couple that has a history of miscarriage
• To examine any child or baby who has unusual features or developmental delays

The bone marrow or blood test can be done to identify the Philadelphia chromosome, which is found in 85% of people with chronic myelogenous leukemia (CML).

The amniotic fluid test 完成 to check a developing baby for chromosome problems.

Your provider may order other tests that go together with a karyotype:

• Microarray: Looks at small changes in the chromosomes
• Fluorescent in situ hybridization (FISH): Looks for small mistakes such as deletions in the chromosomes

正常的结果

正常结果是:

• Females: 44 autosomes and 2 sex chromosomes (XX), written as 46, XX
• Males: 44 autosomes and 2 sex chromosomes (XY), written as 46, XY

What Abnormal Results Mean

Abnormal results may be due to a genetic syndrome or condition, such as:

• 唐氏综合症
• Klinefelter syndrome
• Philadelphia chromosome
• 称18三体综合症
• 特纳综合征

Chemotherapy may cause chromosome breaks that affect normal karyotyping results.

风险

风险 are related to the procedure used to obtain the sample.

In some cases, a problem may occur in 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.

参考文献

Bacino CA, Lee B. 细胞遗传学. 在:Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21艾德. Philadelphia, PA: Elsevier; 2020:chap 98.

马佩尔，施泰因. Applications of cytogenetics in modern pathology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 71.