Karyotype Test: Types, Uses Purpose, Procedure and Results

Overview 

A karyotype test helps examine blood or body fluids for the presence of abnormal chromosomes. The doctors often recommend the test to identify any genetic diseases or disorders in babies still developing in the womb.

What is a karyotype test? 

The karyotype test uses body fluids and blood to analyze chromosomes. Chromosomes are the parts of the cells of the body that contain genes and genes consist of DNA. Humans inherit genes from their parents. Genes determine numerous traits, such as eye and skin colour. Human beings have 23 pairs of chromosomes. 

A person receives genes equally from both the parents, i.e. one half from their mother and another half from their father. Sometimes, a fetus may receive an extra chromosome or may not include certain chromosomes. Their chromosomes may be abnormal in size, shape, or sequence. Abnormal  chromosomes indicate that a fetus may be born with a genetic disease or disorder. 

What are the uses of karyotype tests? 

As cited above, humans have 23 pairs of chromosomes. Sometimes, a person may have an extra chromosome, a missing chromosome, or an abnormal chromosome. Karyotype tests can help identify if any of these have happened. The most common defects that doctors look for with karyotype tests are: 

• Down syndrome (trisomy 21): In this genetic condition, a person has an extra, or third, chromosome 21. It affects the person’s appearance and mental and learning ability. 
• Edwards syndrome (trisomy 18):  This genetic disorder, a person has an extra 18th chromosome. 

Patients with Edwards syndrome suffer from several health-related issues; most do not survive longer than a year.

• Patau syndrome (trisomy 13): A person has an extra 13th chromosome. Patients with Patau syndrome usually suffer from heart problems and severe mental impairment. The survival rate of patients with Patau syndrome is not more than a year. 
• Klinefelter syndrome: The male  has an extra X chromosome (XXY). The patient with Klinefelter syndrome may go through puberty at a slower pace and may find it challenging to have children. 
• Turner syndrome: A female has a damaged or missing X chromosome. It leads to heart problems, neck problems and short height. 

The doctors may recommend Karyotype tests also to find other underlying health issues, such as: 

• A disorder that one could pass down to their child.  This could include checking an unborn baby or a child for genetic disorders 
• Chromosomal disorders  that may have led to trouble getting pregnant or several miscarriages
• Genetic issues leading to stillbirths 
• Diagnosis and treatment plan for some kinds of cancer and blood disorders 
• The cause of specific physical or developmental problems in newborn babies or young children. 

What are the types of karyotype tests? 

To perform a karyotype test, your healthcare provider will take a sample of your cells. The most common ways to get a sample include:

• A blood test. For this test, a health care professional will take a blood sample from a vein in your arm, using a small needle. 
• Chorionic villus sampling (CVS) or prenatal testing with amniocentesis: Chorionic villi are tiny growths found in the placenta. In Amniocentesis test, a long needle is inserted  through the abdomen of a pregnant woman to collect samples of a small amount of amniotic fluid. 
• Bone aspiration and biopsy: The doctor collects samples of the bone marrow , this being used for diagnosis of hematological malignancies or blood disorders 

It’s more likely for a baby to have a chromosome problem if: 

• A parent is 35 or older. 
• Another child or a family member with a chromosome disorder. 
• One or both partners have abnormalities  in their chromosomes. 

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When is a karyotype test needed? 

Adults may need karyotype testing if they: 

1. Have certain cancers or blood disorders such as anemia, leukemia, lymphoma or multiple myeloma. Finding these abnormalities with karyo typing can guide the doctor toward planning for better treatment. 
2. Face issues getting pregnant or getting their partner pregnant. Sometimes male infertility or female infertility is the outcome of a genetic disorder. 
3. Have a family history of genetic diseases. Chromosome analysis can help determine if a person has abnormal chromosomes and the chances of passing them on to your children. 
4. If a baby dies late in pregnancy or during birth, a karyotype test may help identify if a certain type of genetic disorder may have been the reason for death. Newborns or young children may need chromosome analysis if they have a genetic disorder. There are many genetic disorders, each with varied symptoms. 

What are the complications of karyotype tests? 

There are no such significant risks with a blood test, but one may experience: 

• Bruising 
• Soreness on the inside of the arm 
• Light bleeding at the location of needle insertion

Risks of bone marrow aspiration and biopsy include: 

• Bleeding 
• Pain or soreness at the injection site 
• Bruising 
• Infection 
• Tingling in the legs 

Risks of amniocentesis or CVS include: 

• Cramping 
• Bleeding 
• Miscarriage  
• Infection in the uterus 

Conclusion 

A karyotype test examine blood or body fluids for any abnormal chromosomes. 

Adults, children or fetuses may need this test if they risk passing on or getting a specific genetic disorder. Counselling can help weigh the risks and benefits of chromosome analysis. 

Frequently Asked Questions (FAQs)

How long does it take to get the results?

Typically, the patient may receive the test results in 8-10 working days.