Genetic Testing and Beta Thalassemia


When a year old Moinam’s parents noticed his pale appearance and tiredness, they consulted a physician near their home in Siliguri. His blood test showed alarmingly low hemoglobin count. But the doctor prescribed an iron-based tonic without concluding, thinking that he was suffering from a minor form of anemia.

However, later it was discovered that he had beta-thalassemia. Until he was recommended for stem-cell transplantation, he had to continuously undergo regular medication and blood transfusion.

After the stem-cell transplantation, his blood tests started showing positive results and his parents; who are carriers of thalassemia, were relived.

Just like Moinam, around 10,000 to 12,000 babies with major thalassemia syndrome are born each year in India.

It has been estimated that there are around 30 to 40 million carriers of beta-thalassemia in the country. In spite such alarming numbers, very little is known about this disease.

Because of the complexities, thalassemia is considered as a dreadful disease. However, isn’t it surprising that bollywood superstar Amitabh Bachchan also has thalassemia minor yet perfectly leading a normal life and continues to entertain us?

About Beta-thalassemia

Beta-thalassemia is a blood disorder that causes decreased production of hemoglobin, a molecule that carries oxygen throughout the body.

People with a mutation only in one copy of gene have thalassemia minor. Thalassemia minor results in zero or very slight anemia.

Thalassemia major occurs when child acquires two mutated genes, one from each parent.  Children born with thalassemia major usually develop the symptoms of severe anemia within the first year of life.

Beta-thalassemia is most common in African American, Asian, Hispanic, Mediterranean and Middle Eastern populations than other populations.

Effects

Reduced amounts of hemoglobin cause a shortage of red blood cells, called anemia. Severe anemia can cause a person to be pale, short of breath, easily tired, and have poor growth. Frequent infections and blood clots are also associated with anemia. The severe type of beta-thalassemia, called Cooley’s anemia, or beta-thalassemia major, causes life-threatening anemia, failure to thrive, poor growth, jaundice, and enlarged organs including the liver, spleen, and heart.

How it is inherited?

Beta-thalassemia is an autosomal recessive disorder, which means that a couple might have a child with beta-thalassemia only if both reproductive partners are carriers. When both reproductive partners are carriers of beta-thalassemia, there is a 25% chance of each child having the disease.

Beta Thalassemia inheritance

 

Genetic testing helps.

There are two tests available for testing if you’re either a carrier or a beta-thalassemia major:

  1. Complete Beta thalassemia (HBB) gene analysis:

This test analyzes the HBB gene for all the mutations that may cause Beta-Thalassemia, by Sanger sequencing.

2. Genetics Screening for Beta Thalassemia                    (5 common mutations):

 This test analyzes the 5 most common mutations in the HBB gene that may cause Beta-Thalassemia, by Sanger sequencing. These common mutations are the most common ones found in 90% of Indian population. Both of the above tests require a sample of 4 ml whole blood.

The results–

If you are a carrier of beta-thalassemia, the next step is to have your partner tested to check if she/he is a carrier too.
If your partner is tested and is not a carrier then the chance of the two of you having a child with beta-thalassemia is low. Speak with your doctor or genetic counselor for recommended next steps.
If your partner is tested and you both are carriers of beta-thalassemia, then there is a 25% chance that each child will have beta-thalassemia. This chance is the same regardless of your ethnic background or your family history.

Since beta-thalassemia is an inherited disease, your close family members are at increased risk of being carriers as well. It will be better for them if they get tested too.

What are the treatments?

 Treatment for beta-thalassemia includes regular blood transfusions. In some cases, a stem cell transplant can cure the disease. This is necessary to provide a temporary supply of healthy red blood cells with normal hemoglobin that the patient’s body needs. Nowadays, drugs designed to remove excess iron (iron chelators) have significantly changed the prognosis of thalassemia.

Apart from proper medication and keeping check on iron content in diet (as the iron overload may cause complications with major organs), a typical day in a life of child with beta-thalassemia is pretty normal.

Thus, medical advances continue and promise to improve the life expectancy and quality of life further for those living with thalassemia.

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Personal Genome Analysis – A Test to know yourself better


On April 6, 2003, NBC journalist David Bloom, 39 died after spending long hours in a tank with limited mobility while covering Iraq invasion. Later it was discovered that it was a pulmonary embolism — a blood clot that moved from the leg to the lung. It is caused by a condition called deep-vein thrombosis. He wasn’t aware of the fact that he was genetically predisposed to blood-clots. If he had known about this condition, his life would have been saved with precautionary measures. Knowing your genetic condition is very important, which is highlighted from the above incidence.

DNA in cells governs many of your physical characteristics like height, colour of eyes, texture and colour of hair, and so on. Genes are inherited from the biological parents and that’s how characteristics of your parents and grandparents affect the children. Along with characteristics, other factors like risk to certain physical conditions/ diseases are also caused by genetic predisposition. E.g. Obesity is caused by genetic predisposition in 70% cases. That is why it becomes very important to know and explore your genes.

Genome exploration means revealing the information on one’s genome using the landmarks or Single Nucleotide Polymorphism which would help us reach a particular risk or predisposition. Genomes are the set of genes or genetic material present in a cell.

Genetics is important because of the below mentioned factors-

  • Blue print of our individual existence.
  • Plays crucial role in treatment of various diseases.
  • Genetic diseases which are undiagnosed or diagnosed late.
  • Affects quality of life.

It helps clinicians as they can utilize genetic discoveries to provide efficient drugs and predictive information to create personalized lifestyle management for you. It also develops therapeutics and health management tools to help prevent disease and engage individuals to actively participate in their healthcare decisions.

Genome-wide association study (GWAS) and Indian population

When adapting genome tests for India; diseases, disorders, and other conditions specific for Indian region need to be considered. Beta Thalassemia is the most common genetic disorder. Specific mutations for Beta Thalassemia, which are well known to be present in Indian population, are analyzed.

Next, all the allele frequencies are adapted according to the actual frequencies in Indian population. This was done using the genotyping data, processed till date (more than 1 000 people), for every single mutation. Valid allele frequencies are important as they affect the final risk calculation for development of the disease.

Personal Genetic Analysis is recommended for you if:

You have a family history of certain diseases.

You would like to adjust your lifestyle according to your genes.

You want to know your risks and hidden talents.

You realize that prevention is better than cure.

In the PGA report, your risk of getting a particular condition/disease is given in comparison with the risk in general population. Risk does not mean presence of disease or certainty of developing the disease, because both genetic as well as environmental factors are responsible for the onset of a disease. E.g. Genes influence Iron Metabolism in about 30% of cases while diet and environment influence iron metabolism in 70% cases.

The report also reveals your inherent metabolic response to various food components like carbohydrates, fats, protein and various vitamins.

PGA DTR

 “Our genomes truly are a fundamental part of us. They are what make us human, including the distinctively human ability to learn and create culture. They account for at least half of what makes us different from our neighbors. And though we can change both inherited and acquired traits, changing the inherited ones is usually harder.”– Steven Pinker, Cognitive Scientist.

 

 

 

 

 

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Cardio diabetics and Pharmacogenetics


On 2nd July 2008, David Belk, 50, director of a construction firm died of brain hemorrhage. He headed the ball during a veterans’ soccer match. Doctor said that even if he would have been taken to the hospital immediately, he wouldn’t have been saved! So what lead to his death? Mr. Belk, father of two, had a heart pacemaker fitted ten years earlier and was on oral warfarin for anticoagulation which can lead to weakening of blood vessels in the head.
Excessive anticoagulation could have been avoided by Pharmacogenetic tests.

From the above case, you must have realized how important is it to know that which drugs suit our genetic makeup and which don’t.

When we tend to get a common cold or fever, more often than not, we take some medicines on our own without any clinical supervision. Very little do we know how harmful this practice is. Recently, genetic studies have discovered that medicines don’t always work the same way for everyone and could even be fatal to some.

The Indian Pharmacopoeia Commission expressly recognizes that genetic make-up of an individual can impact drug metabolism by as much as 6 to 8 fold and therefore can cause life threatening side effects.

A part of it is genetics and through pharmacogenetics one can learn how you respond to certain medications. The results range from whether the drugs are beneficial, need a different dose due to sensitivity and adverse effects, or even have increased risk for other conditions.

Image credits- ultrasoundschoolsinfo.com
Image credits- ultrasoundschoolsinfo.com

Pharmacogenetics provides personalized drug therapy depending on your genetic makeup, thus maximizing the chances of getting the proper treatment and limiting adverse effects of drugs.

Cardio Diabetics

If you or anyone you know is undergoing a treatment for any cardiovascular disease, it’s advisable to take help of pharmacogenetics. It can help to take well-informed course of treatment for the cardiovascular cases.

This case study will help you to see how pharamacogenetics tests helped a cardiovascular patient.

A 45-year-old man was diagnosed with acute inferior myocardial infarction and underwent emergent coronary angiography (CAG). Two bare-metal stents were deployed in the right coronary artery. After the procedure, antiplatelet therapy with 75 mg Clopidogrel daily was given. However, stent thrombosis occurred three times and he underwent repeat interventions. To investigate the cause of repeated stent thrombosis, the platelet function was measured. The result showed that he did not achieve an adequate antiplatelet effect.

Know the right medications for you!

  1. Get a genetic test to determine your metabolic status. It’s important to be aware of the type of metabolizer you are for each cytochrome P450 enzyme. GeneshieldTM Cardio-Diabetic test at Datar Genetics Limited would help you and your clinician to alter you present medications or dosage. This test has turnaround time of 2 weeks and needs 4ml whole blood/saliva.
  2. Review your results. Know which drug is most effective for you and which wouldn’t have any adverse drug reaction (ADR) on you.

Your result will look like this

Share the information with your doctor and ask them to make changes accordingly in your prescription.

This test also helps you take control of your overall cost of medication by identifying the right medicine for you, from the beginning of the treatment. So talk to your doctor today.

 

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Pharmacogenetics – Selecting Right Drugs For the Right Genes


Did you know that 87%of the total patients receiving cancer chemotherapy develop Adverse Drug Reactions (ADR)? It also causes 50 deaths out of 1000 patients in India. These statistics highlight the importance of correct drugs for the treatment.

Depending on your genetic makeup, some drugs may work more or less effectively for you than they do in other people. Likewise, some drugs may produce more or fewer side effects in you than in someone else.

Pharmacogenetics is the study of inherited genetic differences in drug metabolism which can affect individual responses to drugs, both in terms of therapeutic effect as well as adverse effects. It plays an important role in Oncology.

Now, doctors are able to use information about your genetic makeup to choose the drugs and drug doses that are helpful to you.

For example, if a patient asks for extra amount of codeine to relieve the pain, it can come across as a sign of an evading patient seeking narcotics. However, that patient can be breaking down the codeine within minutes of swallowing it and therefore not be able to create the intermediate molecule that relieves the pain. With this conclusion, the physician can suggest the suitable drugs.

image credits- static1.squarespace.com/
image credits- static1.squarespace.com/

Pharmacogenomics also help to save you time and money as the “best-fit” drug for you can be chosen from the beginning of the treatment to avoid the trial-and-error approach of giving you various drugs.

Besides pharmacogenomics, other factors may influence how a person reacts to a drug. These include:

  • Person’s age and gender.
  • How advanced the cancer is.
  • Person’s lifestyle habits, such as smoking and drinking alcohol.
  • Other diseases that they have and the medications they are on for these conditions.

FDA Guidelines for Pharmacogenetics

The U.S. Food and Drug Administration (FDA) has listed many drugs that need genetic testing before introducing them in the treatment. Some of them are Mercaptopurine and Irinotecan. FDA recommends genetic testing before giving the chemotherapy drug mercaptopurine (Purinethol) to patients with acute lymphoblastic leukemia. It also advises doctors to test colon cancer patients for certain genetic variants before administering irinotecan (Camptosar), which is part of a combination chemotherapy regimen.

Let us see some case studies so that we can understand how pharmacogenetic analysis helped patients with better drugs, and thus, treatment.

  1. A 62 year old male patient with colon cancer was started with a standard dose of FOLFOX and after 6 weeks, Irinotecan and Cetuximab were introduced. However, after the first cycle, sever Myelo-suppression was developed. It delayed the chemo for 3-15 days every cycle. At DGL, comprehensive pharmacogenetic analysis consisting of tumour mutation analysis was advised which confirmed ADR to Irinotekan and 5FU and capsitaben was recommended.
  1. 52 year old male Chronic Smoker diagnosed with adenocarcinoma of the Right Lung with liver metastasis was given Pemetrexed and Carboplatin- 6 cycles which showed partial response. He was advised comprehensive pharmacogenetic analysis at DGL consisting of Tumor mutation analysis for efficacy evaluation and Pharmacogenetics for toxicity profile that showed KRAS mutation which explains partial response to Pemetrexed. Other mutations detected suggestive of personalized targeted therapy.

Geneshield Test at DGL

This test at DGL requires sample of whole blood/ saliva and turnaround time is 2 weeks. The report will give you the information of the genetic mutations you carry that would affect the efficacy of drugs. This test also gives you information about the toxicity of these drugs on your body at the same time.

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It’s always better to maintain a good rapport with the doctor. Here are the few things which you should discuss with your doctor before starting a treatment.

  • Would you explain my treatment options?
  • Which treatment or combination of treatments do you recommend? Why?
  • What are the possible side effects of this treatment?
  • Is there a way to predict how the cancer will respond to this drug or whether I might experience severe side effects?
  • What are my options if the cancer does not respond to the drug or if I suffer from severe side effects?

Detecting the ill-effects of drugs and replacing them with proper ones under expert advice definitely help to give the treatment a right direction.

 

 

 

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Liquid Biopsy – A Path Breaking Weapon Against Cancer


Liquid Biopsy

As the medical field is making great advancements with regards to technology and treatments, the tests are narrowing down to more easier yet micro level. Cancer tests have also become more specific and advanced and the perfect example is Liquid Biopsy.

Liquid Biopsy is a new, non-invasive technique that detects disease biomarkers released by tumour in blood, urine or other bodily fluids. When cancer spreads,it sheds cells and DNA fragments in the blood. Datar Genetics Ltd. has developed this technique for finding cancer cells, RNA from exosomes and tumour DNA fragments in the blood. In this method, you get similar information from a simple blood test which you would have to otherwise get from a tissue sample obtained from the regular invasive biopsy. Conventional biopsies taken from tumor sites may suffer from biased results due to tumour heterogeneity whereas liquid biopsy is free from such biases.

Liquid Biopsy targets one of the following:-

  1. Free circulating nucleic acids.
  2. RNA expression and fusion transcripts.
  3. Circulating tumour cells.
  4. Multiple DNA abnormalities
  5. Tumour Emboli
  6. Insertions and deletions
  7. Trans-locations and chromosomal abnormalities
  8. Point mutations

LB2

You should consider Liquid Biopsy when:-

  1. Enough tissue cannot be obtained from the initial invasive biopsy.
  2. Cancer starts in a place that is difficult to access by surgical biopsy.
  3. Cancer spreads to brain, bone,lung or other difficult to biopsy locations.
  4. Recurrence of cancer post initial tumour removal.
  5. Patient isn’t responding to treatment the way you expect.
  6. The patient doesn’t want a repeat biopsy.

In Cancertrack – Liquid Biopsy by Datar Genetics Limited, capturing and detecting CTCs, exosomes, ctDNA and other bio-markers has an important predictive and therapeutic implication. Detection of tumor DNA has clinical utility in risk stratification in early cancer, in early detection of relapse and in monitoring the response to treatment.

This test has two types- A prognostic test may indicate the outcome and course of a disease. A predictive test suggests likely response to the particular therapy. It is also devised to screen for cancer. It will inform you about your current status of cancer and is intended to provide clinicians information on the presence of specific biomarkers in the CTCs.

The major advantage being cancer treatments getting more personalised and micro-level, Liquid Biopsy proves very helpful and indeed a boon for us.

 

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