All posts by yechangenetics

The Role of Genetic Counselors in Society

Genetic counselors, as members of healthcare team, provide information and support to people at risk of or affected by genetic diseases. They act as a source of information about genetic diseases for patients, healthcare professionals, and the general public.
To identify families at risk of genetic disorder, genetic counselors gather and analyze family history, patterns of inheritance and calculate chances of reappearance. They offer information about genetic testing and associated procedures. Genetic counselors are trained to present difficult-to-comprehend and complex information about genetic testing, risks, and diagnosis to patients and families. They help people to understand the significance of genetic diseases about personal, cultural, and familial contexts.
Genetic counseling sessions include a pre-testing and post-testing session. In the initial genetic counseling, the genetic counselor determines why the patient is seeking genetic counseling. They collect and record a medical history of the patient’s family, and assess the psychological and medical history of the patient. If the patient asks for a genetic testing, the genetic counselor is often the person who communicates the results.
In general, the role of genetic counselors is to increase the people’s understanding of genetic disorders, help family and individual identify the psychosocial tools needed to face potential outcomes and to reduce the family’s anxiety.
References
https://www.ncbi.nlm.nih.gov/books/NBK115552/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666564/

Genetic Testing Before and During Pregnancy

Genetic testing before and during pregnancy is given to expecting or prospective parents to look for unusual genes that can cause certain diseases in their baby. Many genetic diseases are referred to as recessive disorders,” meaning that each parent must pass along an abnormal gene to the child for the child to get the disorder. In other words, if one parent screen positive for a genetic disorder but his/her partner does not, the child will not inherit the disorder. And even if both parents screen positive, there is only 25% chance the child will have the condition.
Ideally, genetic testing is done before parents start trying to get pregnant. However, because many pregnancies are accidental, many couples go for genetic testing early in pregnancy.
Getting screened before you get pregnant can help you make an informed decision or reassure you. If it turns out that couples are carriers of a certain genetic disease, they can start preparing to live with a child that has a genetic disease, choose to learn about various prenatal tests to check if their baby is healthy, or they can consider other options such as sperm or egg donation or adoption.
Once you get pregnant, getting tested can help you decide the right prenatal tests for the baby, and what to look for if you decide to have them. For instance, if you know your baby is at increased risk for having sickle cell disease or cystic fibrosis, your physician can look for those disorders specifically through either amniocentesis or a CVS(chorionic villi sampling)
References
http://www.parents.com/getting-pregnant/genetics/tests/genetic-testing/
http://kidshealth.org/en/parents/genetics.html

What is “Phantom Pain?”

Phantom pain sensation refers to a person’s feeling related to limbs or organs that are physically not a part of their body. For example, let’s say that a part of a person’s body, such as an arm, was amputated because of an accident. If the person has a phantom pain sensation, then he would feel pain in the position where his arm supposed to exist, even though he doesn’t have an arm (this particular phantom pain related to the limbs are called phantom limb pain).

Then why do these kinds of phenomenon occur? According to the scientists, when a part of a body is amputated, then the region of the brain that was needed for the control of that part of the body is no longer needed, and the neuronal system in the part of the brain falls into disarray. To fill the empty spots in the brain, those parts of the brain take over the tasks of the neighboring neurons and become rearranged to do different things. However, when the brain tries to adapt to the new situation, in some cases this process goes wrong, which eventually causes the phantom pain.

As you can see, there are no apparent causes of the phantom pain discovered by scientists because there might be other reasons other than the cerebral shifts such as inherited nerve damages. However, using fMRI, a method to distinguish the active parts of the brain while it’s working, scientists have discovered that degree of the shifts related to the functions in our brain caused by amputation (and many other factors) is directly proportional to the intensity of pain the patient receives through the phantom pain. Also, researchers found out that a person with a functional artificial limb has felt less phantom limb pain than the patients that do not have it.

Even though it might take some time, a cure for phantom pain keeps on developing as the researches related to phantom pain proceed. I hope that later, the patients would not suffer from their phantom pain, or, in my own words, “false pain.”

 

References

12 July, 2017 – Episode 627 – This Week in Science Podcast (TWIS)

http://www.twis.org/broadcasts/

https://en.wikipedia.org/wiki/Phantom_pain

Researchers Look at Genetics That are Linked to Chicken Weight Gain

To help farmers in their quest to increase the weight of their roosters and hens, researchers have been interested in searching for the specific genetics behind weight gain in chickens, known scientifically as Gallus gallus.
Using a distinctive experimentally-bred population, scientists from Uppsala University researched the genetic architecture behind chicken weight. Led by Örjan Carlborg, the research team used two different bred lines of Plymouth Rock chickens to explore weight adaptation. In their study, the researchers used an advanced inter-cross line which was founded by breeding the low and high weight lines after forty generations of selections. In the high-weight line, the average 8-week body weight was 1.412kg compared to the low weight counterparts that weighed 170 g. (About 12 % of body weight compared to the high weight line)
Using the 15th generation of the inter-cross line between the low and high weight lines, the scientists identified 20 genetic loci. Examination of these genetic loci allowed scientists to explain over 60 % of the additive genetic variance for the particular trait.
The researchers further focused on few genetic hotspots (7 of 20 genetic loci), referred to as quantitative trait loci. They found that only two could be mapped to one, well-defined loci; others had linked loci with numerous gene variants. The comprehensive dissection of the loci that contribute to the polygenic adaptations in chicken lines does provide a good understanding of the genome-wide mechanisms that are involved in the long-term selection responses.
Although the selection responses for weight were due to numerous loci of small individual effect, the genetic mechanisms in the specific loci were more complex than presumed in the model. The researchers now hope to further examine this chicken model system to increase understanding of the genetic mechanisms of weight adaptation.
References
https://www.sciencedaily.com/releases/2017/07/170718221902.htm
http://www.poultryworld.net/Genetics/Articles/2017/7/Scientists-look-at-genetics-behind-chicken-weight-gain-161926E/

Major Study has Identified Common Genetics Variants Linked to Muscle Strength

In a genome-wide association study, scientists from the University of Cambridge have identified 16 genetic variants that influence muscle strength in humans. The findings were published last week in the journal of Nature Communications.
According to senior author Professor Nick Wareham, the study highlights the role played by muscle strength in the prevention of the complications and fractures which often follow a fall. The researchers used data on hand grip strength from over 142,000 participants in the UK Biobank study and over 53,000 additional participants from the UK, Denmark, Netherlands, and Australia.
According to Dan Wright, an author and a Ph.D. student at the Medical Research Council Epidemiology Unit at the University of Cambridge, the very large number of participants in the UK Biobank offer a powerful resource for recognizing genes that are involved in complex traits like muscle strength.
The 16 genetic variants associated with grip strength are POLD3, ERP27, TGFA, HOXB3, PEX14, GLIS1, MGMT, SYT1, LRPPRC, GBF1, SLC8A1, KANSL1, IGSF9B, DEC1 ACTG1, and HLA. Most of the highlighted genes play a role in biological processes relevant to the function of muscle, including function and structure of muscle fibers, and the communication of muscle cells with the nervous system.
Using the 16 genetic variants, the researchers were able to examine the hypothesized causal link between adverse health outcomes and muscle strength.
References
http://www.sci-news.com/genetics/common-genetic-variants-muscle-strength-05035.html
http://www.cam.ac.uk/research/news/common-strength-genes-identified-for-first-time

Importance of Knowing Your Family Medical History

A record of health information about an individual’s close relatives is known as a family medical history. A complete record contains information from at least three generations of relatives, including parents, sisters and brothers, uncle and aunts, nephews and nieces, cousins, grandparents, and children.
Families have numerous factors in common, including their lifestyle, environment, and genes. Together, those factors may determine medical conditions that may exist in your family. By observing disorders pattern among relatives, professional in the healthcare field can determine whether future generators, a person, or other family members may be at risk of developing a specific condition.
A good family medical history enables healthcare professional to identify individuals with a higher-than-usual likelihood of having some disorders, such as diabetes, certain cancers, stroke, high blood pressure, and heart disease. These disorders are influenced, to a large extent, by a combination of environmental conditions, lifestyle choices and genetic factors. Also, a family history can shed some light on the risk of rarer disorders caused by mutations, such as sickle cell disease and cystic fibrosis.
Although a family medical record can provide information about the likelihood of a person to develop a particular disorder, having relatives with certain medical conditions does not mean a person will certainly develop those conditions. An individual with no family history of a condition, on the other hand, may still be at risk of having that condition.
References
https://ghr.nlm.nih.gov/primer/inheritance/familyhistory
https://www.ncbi.nlm.nih.gov/books/NBK115560/

Understanding Genetic Variation

geneticvariation-02

Genetic variation is a term that is used to describe the DNA sequence variation in human genomes. It is what makes all people unique, whether in terms of skin color, the shape of our faces, or hair color. Although individuals of same species have similar characteristics, they are rarely identical. That difference in those individuals is referred to as variation.

Amongst people, single nucleotide polymorphisms are the most common type of genetic variation. Each nucleotide polymorphism denotes a difference in a base of single DNA. In a person’s DNA, DNA bases are A, C, G or T.

Genetic variation is a result of different alleles of genes. For instance, looking at eye color, individuals with blue eyes have a unique allele of the gene for eye color, while individuals with brown eyes have a different allele of the gene.

Face shape, height, skin tone and eye color are all determined by our genes. Therefore, any variation that occurs is due to the genes we inherit from our parents. In contrast, while weight is partly influenced by genes, it is highly influenced by environment. For example, how often we exercise and how much we eat.

References
http://www.yourgenome.org/facts/what-is-genetic-variation
https://www.nature.com/scitable/topicpage/the-genetic-variation-in-a-population-is-6526354