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/

Tongues ‘taste’ water by sensing sour

All we know about water is that water is an odorless, tasteless, slightly compressible liquid when it’s pure. However, when we drink water, we can know that it’s water. It might be unsurprising to notice that we’re drinking something liquid. But how do we know that it’s water, not syrup? Then, does it mean that water has a taste? – actually not. According to the new study, we can recognize the water not by tasting the water itself, but by sensing acid which is produced when we drink water.

All mammals need water to sustain their life. When we drink water, we have to drink the water through our mouth.According to Yuki Oka who studies the brain at the California Institute of Technology in Pasadena, our tongue has evolved to detect some necessary materials for survival like salt and sugar. This, in other words, means that the sense of detecting water would have evolved.

It is already found that a brain area called the hypothalamus controls thirstiness of mammals. But a brain cannot decide the taste of something alone because, in order to taste something, the brain should cooperate with a mouth and receive a signal from it to know what the person’s eating or drinking. Oka says, “There has to be a sensor that senses water, so we choose the right fluid.” If we cannot distinguish the water from others, we might make a fatal decision, such as drinking poison instead of water.

To prove the water sensor, Oka and his group used mice. They dripped different flavors of liquid onto mice’s tongues. They observed a signal from the nerve cells attached to the taste buds when they were drinking, and mice showed a great nerve response to all tastes. However, the main point is that they reacted to water similarly. Somehow, the scientists discovered that taste buds are able to detect water.

Our mouth is filled with a lot of saliva— a mixture of enzymes and other molecules. Also, the mouth includes bicarbonate ions (HCO3-), which make saliva more basic. The pure water has lower pH than basic saliva. When we pour the water into the mouth, it washes out the basic saliva and enzymes in our mouth instantly starts to replace the ions. It combines carbon dioxide and water to produce bicarbonate. As a side effect, it also produces protons. The bicarbonate is basic, but the protons are acid. Then, the receptors on our tongue detect acid that we usually call ‘sour flavor’ and sends a signal to the brain.

To confirm this, Oka and his group used a technique called optogenetics. In this method, scientists insert light-sensitive molecules, which trigger an electrical impulse when shone with light, inside cells. With this principle, Oka’s team added a light-sensitive molecule to the sour-sensing taste bud cells of mice. As they shone the light to their tongues, they started to lick the light as if they lick the water. By stimulating acid sensor, they misunderstood it as water.

To the other group of mice, Oka’s team removed the sour-sensing molecule by blocking the genetic instructions that make this molecule. As a result, they weren’t able to know whether what they’re drinking is water or not. They even drank thin oil instead. Oka and his group published their results on May 29 in the journal Nature Neuroscience.

Scott Sternson, who studies brain’s mechanism for controlling animal behavior at a Howard Hughes Medical Institute research center in Ashburn, VA, says it’s crucial to learn how we sense simple but vital things, such as water. “It’s important for the basic understanding of how our bodies work,” he says.

Some people might think it’s a weird concept that the water has a sour ‘taste’. Flavor is a complex interaction between taste and smell. So, detecting water is quite different with tasting. Water may still taste like nothing, but to our tongues, it’s definitely something.

Reference: https://www.sciencenewsforstudents.org/article/tongues-taste-water-sensing-sour

 

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

What is CRISPR Cas9?

Have you ever heard about hemophilia? It is a rare genetic disease that disables people from clotting blood. There is not yet therapy for hemophilia. However, a new technology to change the genes related to hemophilia was developed recently. The key point in this new technology is CRISPR-Cas9. It is genetic engineering tool which enables people to cut specific region of DNA and to insert another homologous DNA. Cas9 and guide RNA (gRNA) are important molecules in CRISPR-Cas9.

Cas9, a restriction enzyme, was first discovered in the 1980s. When a virus infects a bacteria, the bacteria cut the intruder’s DNA by using Cas9.

gRNA is made from a small piece of pre-designed RNA sequence. gRNA helps the Cas9 enzyme to cut particular regions of DNA.

CRISPR stands for Clustered Regularly Interspersed Short Palindromic Repeats. Also, Cas means “CRISPR associated.” Even though this method does not destroy surrounding genes, it is possible to change a particular DNA sequence. Treatments for hemophilia using CRISPR-Cas9 are being studied now in the USA. Researchers say, “If a ‘normal blood clotting factor’ gene is inserted into a hemophilia patient, his or her blood will be clotted.”

In addition to hemophilia, CRISPR therapy related to HIV is also being studied. HIV, or Human Immunodeficiency Virus, is a virus that infects the body immune cells and corrupts the immune system.  One typical thing of HIV is that it can go into the immune cell using the specific receptor proteins that are on the surface of the immune cells. Using CRISPR method, scientists found out that getting rid of these proteins makes HIV unable to infect another cell. Then, without the proteins that enables them to infect other cells, HIVs cannot replicate themselves and therefore collapse.

Also, CRISPR is applied to not only curing genetic diseases but also developing plants and animals. By using CRISPR, researchers made MSTN, which limits the growth of pigs, not perform its role. As a result, researchers were able to get a “super pig,” that has more muscles than normal pigs.

The usage of CRISPR can make valuable crops. In 2016, Dr. Yang and his companions made new mushrooms that doesn’t turn into brown by eliminating the enzymes that cause browning in mushrooms. Korean researchers also developed various crops, such as lettuce that has resistance in harmful insects and bean that decreases the level of cholesterol.

Although CRISPR Cas9 is touted through many positive results, it is a controversial topic. For example, CRISPR Cas9 can be used in manipulating embryonic genes, which causes the whole fetus to change. Some countries prohibit this for ethical reasons. In contrast, the Human Fertilisation and Embryology Authority authorized to alter human embryos in the UK in 2016. Even though there are lots of positive effect modifying genes, we must know that there are some ethical issues that we must concern.

References

http://www.alphr.com/bioscience/1001654/darpa-offers-50-million-to-make-crispr-gene-editing-safer
http://news.mk.co.kr/newsRead.php?year=2017&no=461478

http://science.ytn.co.kr/program/program_view.php?s_mcd=0082&s_hcd=0010&key=201706011107334239

https://www.youtube.com/watch?v=2pp17E4E-O8

http://www.yourgenome.org/facts/what-is-crispr-cas9

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