Monday 26 August 2019 ,
Monday 26 August 2019 ,
Latest News
  • Concentrate on your obligations, commitments: Bangladesh to Myanmar
  • Protect migrant workers from middlemen: PM
  • Zia had betrayed Bangabandhu: Quader
  • 2 years of Rohingya influx: 43 murders in camps, 32 killed in gunfights
  • HC orders to remove word ‘Kumari’ from marriage certificate
  • Prepaid metres system ‘unfair’: PMCRC
16 April, 2019 00:00 00 AM

Haemophilia A: Genetic testing and what to expect

verywell health
Haemophilia A: Genetic testing and what to expect

LANA BARHUM  

Genetic testing for Hemophilia A is widely available and includes carrier testing, direct DNA mutation testing, linkage testing, and prenatal testing. Affecting more than 20,000 Americans, hemophilia is a bleeding disorder caused by genetic defect where the body is unable to produce one of the factors crucial for clotting. Thus, when a blood vessel is injured, uncontrolled bleeding occurs.

There are two main types of hemophilia. Type A is due to a factor VIII deficiency while type B is due to a factor IX deficiency. Clinically, they are very similar conditions, causing unprompted bleeding into the joints and muscles and internal and external bleeding after an injury or surgery. Repeated bleeding eventually causes damage to the joints and muscles. Hemophilia A is four times more common than B according to the National Hemophilia Foundation.

Role of genes

The X and Y chromosomes determine gender. Females inherit two X chromosomes, one from each parent, while males will inherit an X chromosome from their mother and a Y chromosome from their father.

Hemophilia A is an inherited condition through a chromosome X-linked recessive manner. This means the gene linked to hemophilia is found in the X chromosome, which means that if a son inherits the X chromosome carrying the hemophilia gene from his mother, he will have the condition. The son could also inherit the gene not carrying the genetic condition. Fathers cannot pass the condition to their children.

For females, even if they inherit an X chromosome carrying hemophilia from their mother, they could still get a healthy gene from her father and not have the condition. But getting the X chromosome carrying the gene makes her a carrier, and she can pass the gene to her children.

Genetic testing

Genetic testing is available for people with hemophilia A and their family members. There are several methods of genetic testing to help women find out if they are carriers and to make decisions about family planning.

Carrier testing

Carrier testing involves looking for clotting factors in blood. Women with the hemophilia A gene will have levels that are lower than normal, and some may even have levels so low they have bleeding issues.  

Carrier testing has an accuracy rate of up to 79 percent, but carrier testing alone is not enough to determine if a woman is a carrier. Family history, in addition to the testing, can confirm if a woman is carrying the hemophilia A gene.

Women who can benefit most from carrier testing include those who:

Have sisters with hemophilia A

Have maternal aunts and first cousins on their mother’s side, especially girl cousins, with hemophilia A

Direct DNA mutation testing

It's possible to look for and find mutations within the genes through DNA testing. A blood sample will first be taken from a male family member who has hemophilia A. The blood of the female looking to see if she is a carrier is next checked and compared for similar genetic mutations. DNA mutation testing tends to have high accuracy.

Linkage testing

For some cases of hemophilia A, genetic mutations cannot be found. In these instances, linkage analyses, also called indirect DNA analyses, can track the gene mutation in the family. Blood samples are taken from various family members, especially affected males.

Clinicians will then look for patterns of linked DNA in the person with hemophilia A and compare those patterns of the other family members. Unfortunately, linkage testing isn’t as accurate as other methods of testing, especially instances where affected males are distant relatives.

Prenatal testing

Women with a family history of hemophilia may want to have their unborn child tested. As early as ten weeks into pregnancy, chorionic villus sampling can be completed. This involves taking a small sample of the placenta and testing the DNA to look for genetic specific mutations.  

Another test that can be done later in the pregnancy–usually around 15 and 20 weeks into the pregnancy–is an amniocentesis. Using a fine needle inserted into the uterus via the abdomen, a small sample of amniotic fluid is taken. The cells found in the fluid are then analyzed for the hemophilia A gene.

What to expect

Meeting with a genetic counselor is the first step in determining whether someone is a carrier of hemophilia A. Genetic counselors often work with parents who have affected newborns or with women who want to know if they are carriers. They may also meet with men who are assisting in testing of their sisters and daughters.

Meeting with a genetic counselor involves an initial consultation where family and personal history of hemophilia A are discussed. The counselor will then discuss the benefits, limitations, and possible outcomes of genetic testing.

Genetic testing is the next step in providing answers. The type of testing will depend on the family and/or patient’s needs and concerns. Family members who currently have hemophilia A are tested first and then any potential carriers.

Once test results come back, the genetic counselor will meet with the patient and family members to explain results. Discussion may include testing of other family members and getting appropriate medical care.

Insurance may or may not cover the cost of testing. Some insurance providers will allow a physician to explain why testing is needed. Testing is generally approved after such requests.

Genetic counselors can also help patients and their families find necessary resources, including financial assistance and support groups.

A word from verywell

Being a carrier of hemophilia A can significantly affect a woman's life. Many carriers worry about the risk of passing the disease on. They may feel as if having children is not a possibility.

Genetic counselors and hemophilia treatment centers can provide carriers with appropriate counseling, information, and support to help them make decisions and take control of their lives. Moreover, support groups with women in the same situation can be a great source of comfort and hope.

 

Comments

Most Viewed
Digital Edition
More story
Editor Speaks

Editor Speaks

Family medicine service provides complete medical care under one roof for all members of family including children, teenagers, adults, elderly both male…
FAQ on family medicine

FAQ on family medicine

What is family medicine? Family medicine is devoted to comprehensive healthcare for people of all ages. It’s a team approach to caring for you and…
Decline and rebirth of family medicine

Decline and rebirth of family medicine

About sixty years back, at the small and big towns, doctors qualified from medical college or medical schools, established their independent practices.…
Past, present and future of 
family medicine in Bangladesh

Past, present and future of family medicine in Bangladesh

Bangladesh is a small country in South Asia with an area of 1,44,000 sq. km. and a population of over 160 million. It is the 8th most populous country…
Family medicine education in Bangladesh

Family medicine education in Bangladesh

Family medicine is based on the knowledge of the patient in the context of the family and the community, emphasizing disease prevention & health promotion.…
5 Reasons you should have a family doctor

5 Reasons you should have a family doctor

If you have a medical need — sudden flu symptoms, nagging back pain, an unexpected rash — who is your first point of contact? A family physician…
Anti-inflammatory diet: Foods to eat and avoid -- or at least limit

Anti-inflammatory diet: Foods to eat and avoid -- or at least limit

MICHAEL O. SCHROEDER Why eat anti-inflammatory foods? Inflammation is the body's response to injury and disease -- like when you have swelling and…
Build a better bladder

Build a better bladder

A leaky bladder or a sudden urge to go to the bathroom is uncomfortable andembarrassing. But you can take steps to alleviate the problem. "Some people…
9 Silent signs of a vitamin K deficiency

9 Silent signs of a vitamin K deficiency

AMY GORIN, MS, RDN When it comes to nutrients, vitamin K isn't one we hear a lot about, but it's an important one. There are two primary types…
Study supports link between pollution and neuropsychiatric disorders

Study supports link between pollution and neuropsychiatric disorders

A new study led by University of Chicago researchers suggests a significant link between exposure to environmental pollution and an increase in the prevalence…
Lessons in Urology Course held in BSMMU, Dhaka

Lessons in Urology Course held in BSMMU, Dhaka

A unique three day long lessons in Urology Course 2019 held at Shaheed Milton Hall of Bangabandhu Sheikh Mujib Medical University (BSMMU) from August…
High blood pressure in mid-30s may pose risk to brain health

High blood pressure in mid-30s may pose risk to brain health

People in their mid-30s need to watch their blood pressure to protect brain health in later life, says a study. It found the "window of opportunity"…
New drug for people who can bleed uncontrollably

New drug for people who can bleed uncontrollably

Christopher Holmes has haemophilia A - his body lacks a protein that makes blood clot. A simple graze can mean the two-year-old bleeds uncontrollably.…
New drug for people who can bleed uncontrollably

New drug for people who can bleed uncontrollably

A daily pill containing four medicines can cut the number of heart attacks and strokes by a third, a study shows. The polypill contains blood-thinning…

Copyright © All right reserved.

Editor : M. Shamsur Rahman

Published by the Editor on behalf of Independent Publications Limited at Media Printers, 446/H, Tejgaon I/A, Dhaka-1215.
Editorial, News & Commercial Offices : Beximco Media Complex, 149-150 Tejgaon I/A, Dhaka-1208, Bangladesh. GPO Box No. 934, Dhaka-1000.

Editor : M. Shamsur Rahman
Published by the Editor on behalf of Independent Publications Limited at Media Printers, 446/H, Tejgaon I/A, Dhaka-1215.
Editorial, News & Commercial Offices : Beximco Media Complex, 149-150 Tejgaon I/A, Dhaka-1208, Bangladesh. GPO Box No. 934, Dhaka-1000.

Disclaimer & Privacy Policy
....................................................
About Us
....................................................
Contact Us
....................................................
Advertisement
....................................................
Subscription

Powered by : Frog Hosting