Find an article that is relevant to this unit. Here are some possible topics
(1) Why do older mothers have a greater chance of having a child with Down’s syndrome (which is due to an extra chromosome 21).
(2) Find an article on a practical use of stem cells
(3) How has recombination mapping been used to identify disease genes?
Find an article on a specific condition (other than Down’s syndrome) that results either from an abnormal number of chromosomes or a chromosome rearrangement. Write a short summary of the article in your own words. Give the URL.
Post your summary as a reply to this blog.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520824/
Trisomy 18 or Edward’s Syndrome is a genetic disorder in which there are three copies of the 18th chromosome. This condition is the second most common trisomy disorder after trisomy 21 (Down’s syndrome). Edward’s syndrome is similar to Down’s syndrome but it is not as well known because of its incredibly high infant and fetal mortality rate. The rates of live births are not well known because of the high likelihood of termination after a diagnosis is made, but some studies show that about 1/7900 babies have the condition whereas only 1/2123 are born alive. Edward’s Syndrome leads to a variety of health conditions including respiratory issues, cardiac issues, kidney issues, and different facial and hand features. Only 50% of babies born with this condition live past 1 week of age and about 1 in 20 make it past 1 year. Studies show that they usually succumb to respiratory ailments including airway obstruction or aspiration. Infants with Edward’s Syndrome also suffer severe intellectual and physical disabilities.
Similar to Down’s syndrome, Edwards syndrome is often more common in older mothers. It is usually caused by a non-disjunction in meiosis II in the maternal eggs. It can also more rarely be caused by an error in mitosis after a zygote is formed. In a majority of cases, there are three chromosome 18s in every single cell and there are not any normal cells. The cause of these abnormalities is currently unknown. Genetic testing is usually done before the baby is born via amniocentesis. This is done based on the mother’s age and other risk factors.
Currently, there is a large amount of debate about the ethics surrounding Edward’s Syndrome. Many doctors believe that the children born with this condition suffer and do not lead good quality lives and recommend termination once a diagnosis is made. However, most parents with affected children believe that their children are living good, fulfilling lives. There is certainly more research that can and should be done regarding Edward’s syndrome. Hopefully with more genetic information and research, this condition can be better understood and prevented.
https://www.unmc.edu/stemcells/educational-resources/types.html
The relevance of stem cells is becoming greater and greater. Stem cells are cells from which other cells are generated from. They are unspecialized cells that divide into specialized cells with different functions. It is relevant to our class given that we have just learned about meiosis and mitosis. It is a very important tool that will lead to a lot of advancements in the field of medicine. It all started in the 1980s when scientists were able to discover a way to derive embryonic stem cells from early mouse embryos. This was a huge advancement that led to the ability to derive stem cells from human embryos and be able to grow the cells in the lab. The reason for stem cells being so important and relevant is because with more research and resources stem cells can help shape the cure of diseases such as diabetes, blindness, deafness, and much more. This URL attached talks about the different types of stem cells along with the history of stem cells and the importance of them. It is a very nice article, because it contains important information that is easy to follow and is well divided.
Trisomy 13 (Patau Syndrome) is a syndrome that occurs when there is an extra copy of chromosome 13. The reason for this syndrome to occur in a child is due to an older mother, usually older than 35 years old. It can be diagnosed while in the womb or after birth and is caused by a lack of sister chromosomes separating (My article uses the word, nondisjunction, which I had to look up but just means that the cells don’t divide properly). The average life span for a child born with Patau Syndrome is 7-10 days, 90% of children who live past the 7-10 days don’t make it to see their first birthday. Typically, if a patient lives longer than a year, their cerebral and cardiovascular defects aren’t as problematic/serious, thus the reason for them living so long. It occurs in 1/5000 births which is a lower risk than having a child with Down syndrome, which happens in 1/700 births. The physical affects on the face can be cyclopia, cleft lip, and cleft palate. The extremities can experience postaxial polydactyly (extra fingers), congenital talipes equinovarus (club foot), and rocker-bottom feet. Not to mention affects on the heart and other major organs. Most patients who survive past infancy have severe mood disorders, seizures and often fail to thrive. Treatment and corrective surgeries can begin at birth, however even aggressive management and treatments can’t promise a life past one year.
At this time, nothing was stated as far as reasearching more into the syndrome. My take on it is that there is only so much that can be done since on a cellular level, the fetus/child isn’t done developing. This is a syndrome that really has caught my eye and makes me want to follow any research and treatments that may be in development and just wasn’t mentioned.
https://www.ncbi.nlm.nih.gov/books/NBK538347/
https://www.mayoclinic.org/diseases-conditions/turner-syndrome/symptoms-causes/syc-20360782
Turner syndrome is a disease that only affects females. This disease is caused by the alteration or deletion of one of the X chromosomes inherited from the parents. This disease can be diagnosed prenatally but is most commonly diagnosed in early teen years of females. Females with this disease can sometimes be undetected but normally have disformed physical features and often growth issues. Complications from this disease are often heart issues including high blood pressure and malformed hearts. They can also have skeletal issues and many females suffering from Turner syndrome have learning disabilities. There are four genetic alterations that can lead to Turner syndrome and they are Monosomy, Mosaicism, X chromosome abnormalities and Y chromosome material issues. Monosomy is where there is a complete absence of the X chromosome. Mosaicism is when an error occurs in cell division during fetal development and causes some cells to have complete copies of two X chromosomes and others only having one. The X chromosome abnormality is when there are missing parts of the X chromosomes even though there are two copies. The last way that a woman may be affected by this gene is when there is Y chromosome material found within a cell with two copies of the X chromosome. This disease affects around 1 in 2000 women in the United States and researchers continue to push forward to try and solve this genetic issue.
After having a patient this semester with Trisomy 13 I have been fascinated with this condition. When I saw this oppurtunity to do a little research about the condition I jumped at the chance. Trisomy 13, also known as Patau Syndrome, is the third most common trisomy in infants following trisomy 21 and trisomy 18 This condition is associated with ventricular septal defects, cleft lip/palate, retinal dysplasia, central nervous system damage, and many other issues. In this research article, 6320 infants born and hospitalized in the NICU between 1989 and 2010 were analyzed. Of those babies 16 patients had trisomy 13. When looking at the statistics of those 13 babies born the mother’s ages ranged from 20-42 and none of them had any familial history of chromosomal abnormalities. After reviewing the records it was found that although prognosis is often poor in these babies, there was a significantly better survival prognosis in those who received intensive care management, such as, ventilation. Unfortunately, there have been many legal and ethical issues dealing with quality vs. quantity of life.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3372784/
https://www.sciencedaily.com/releases/2021/01/210111084214.htm
Uncovering BAsic Mechanisms Of Intestinal Stem Cell Self-Renewal and Differentiation
At the German Research Center For Environmental Health, researchers are developing ways to identify the mechanisms that regulate the self renewal and differentiation of stem cells in the intestine. Abnormal endocrine system is associated with diseases such as obesity, diabetes, colitis, and cancer. The cause for abnormalities researchers believe is due to an unbalance in the specific types of cells found in the intestine surface which functions can involve nutrient absorption, pathogen neutralization, enzyme and hormone production along with many others. If a detailed map describing the path from a stem cell to a specific cell along with the mechanisms involved for the renewal and regulation can be created, then it opens the possibility that tailored treatments can be developed to mitigate the unbalance of cells involved with chronic conditions.
Stem Cell Research
Stems cells are capable of being developed into cells that serve numerous functions in the body. It is believed that they can be useful for understanding disease, by using them to research causes of genetic defects in cells. Researchers are interested in figuring out how to control differentiation stem cells. These can be used to help restore hearing, and help after a stroke. Differentiated cells can also be used to test the safety of new medications. Stem cells have the potential to have a big impact on health, but there is more to be done before stem cells can be used for successful treatments
https://www.healthline.com/health/stem-cell-research#takeaway
Forgot the website.
Pluripotent stem cells are stem cells that can potentially transform into any other cell. They are extremely useful for research, and are also very rare. However, researchers at Argonne National Laboratory have managed to synthesize them from certain blood cells. Monocytes specifically. The researchers found that when Monocytes were exposed to a growth factor, they created some pluripotent stem cells. After harvesting the cells, the researchers were able to differentiate the cells into nerve, liver, and immune system tissue by delivering more growth factors. This technique could be valuable for transplants and replenishing immune cells after chemotherapy, or even replacing tissue in damaged spinal cords.
https://www.sciencedaily.com/releases/2003/02/030225065929.htm
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4851533/
Both increased maternal and paternal age can be a risk for Down Syndrome. A study was done with the intention to look further into the frequency of the Down Syndrome types and relation with paternal and maternal age. Using 127 children, composed of both boys and girls, suspected to have Down Syndrome with ages ranging from 1-180 months, cytogenetic analysis testing was completed. Cytogenetics tests the structure of DNA within the cell nucleus, in this study it is used by acquiring the peripheral blood lymphocytes. The results of this was a statistical significance of p<0.05. The most frequently appearing type of Down Syndrome was standard trisomy at 86.6% while translocation and mosaicism was at 7.1% and 6.3%. Another finding was that the highest number of Down Syndrome cases was in the mother/father group of ages 30-39 out of ages: younger than 30 and older than 40. Maternal age provided a significant difference in translocation and mosaicism groups while paternal was significant with standard trisomy 21 and translocation.
https://www.hindawi.com/journals/sci/2015/258313/
In this article, Application of Adult Stem Cells in Medicine, discusses the main treatment options for diseases which are either the use of drugs with or without surgery or regenerative remedies, such as stem cell therapy. Stem cells can transform into a mature cell type to help rebuild the tissue. They are used as a form of therapy, which is proven to be safe for utilization. The therapy is performed within a clinic with curing hematological malignancies. This form of therapy, however, is still in some stages of experimentation with its effects of different diseases and/or conditions. Stem cell transplantation has shown to have positive effects for neurological diseases and regeneration of injured nerves. A study was done to assess the findings of bone marrow stromal cell transplantation for individuals with intracerebral hemorrhage. However, there was no long term follow up completed. This demonstrates the lack of research and data with injury and clinical trials. For neurodegenerative disorders, induced pluripotent stem cells are being used to understand the pathogens and its effect on therapy. There is a variety of applications and experimentation done to adult stem cells in regenerative medicine. Hopefully there will be more of a focus in stem cell therapy so there can be more studies done to show the importance of these trials for different diseases.
https://stemcellsjournals.onlinelibrary.wiley.com/doi/full/10.1002/sctm.18-0181
A disease named, periodontitis, is a disease that occurs in the mouth causing inflammation in the surrounding area and causing teeth loss. Periodontal regenerative therapy using stem cells regenerates tissues damaged or lost in the surrounding structures to prevent loss of teeth from occurring. The article takes a look at regenerative approaches using culture-expanded or host-mobilized stem cells and how these are moving towards clinics. The research investigates safe ways to administer this and how to make the stem cells more localized to areas that are damaged in the mouth. The end conclusion states to make this happen, clinical success can be achieved by avoiding the use of external stem cells. The studies involved techniques involving material design and cytokine presentation that permit the patient’s own cells to be used. What they found was that a suitable microenvironment at the injured site can instruct the homing of resident stem cells and can cause the periodontium itself to regenerate again.
https://www.mayoclinic.org/tests-procedures/bone-marrow-transplant/in-depth/stem-cells/art-20048117
Stem cells are cells can develop into many different types of cells. There are embryonic stem cells, adult stem cells, perinatal stem cells. There are more researches about stem cells especially embryonic stem cells. Embryonic stem cells are the cells from embryos that are three to five days old. These cells can be any kinds of cells therefore, it is so useful for understanding how diseases occur. Moreover, it is promising for transplant. These cells can replace the diseased cells or further it can develop to be a new organ. In addition, it is useful for testing drugs. Although there are some ethical issues to use embryonic stem cells for research, the benefits of these research are so valuable.
Why do older mothers have a greater chance of having a child with Down’s syndrome (which is due to an extra chromosome 21).
It was found that there is a minority of mothers(9%) who have their first child after the age of 35. About 20 percent of women have their first child between the age of 30-34. The relevance in this data is that once a woman has passed the age of 30, she will be at increased risk to have some irregularities in chromosomes. Based on a study of mice, the reason for this increased chance of chromosomal irregularities is due to the proteins cohesin and securin being present less in older females. These proteins serve to assist chromosomes in maintaining position(staying in the together in the center). The increased absence of these proteins cause sister chromatids to be loosely connected and even spread apart. This is important because this will lead to uneven chromosome division, which will throw off the number of chromosomes in a mother’s egg cells. All these findings were based on research in mice, so we do not know for sure whether this applies to humans. I would argue it is reasonable to believe that it could apply to humans based on the what we know about down syndrome and factors that correlate to down syndrome in humans.
A women’s age impacts the risk of chromosomal abnormalties especially within women over 32 years old. One chromosomal abnormality that is very common is Down Syndrome. Down Syndrome is a defect involoving an extra copy of chromosome 21. People with Down Syndrome normally have a flattened skull, folded eyelids, slanted eye shape, short stature, etc. Researchers stated that most children or adults that have this defect are usually the last born of a large family and possibly were born before the mother began to experience menopause. There are 3 different types of causes for Down Syndrome and this includes Trisomy 21, Translocation, and a mixture of normal cells that contain two copies of chromosome 21 as well as some cells that contain three copies of the chromosome. The reason why women over 32 years old are more likely to have a high risk pregnancy is because by the time a women is 40 years old, about 60% of her eggs have died or have chromosomal abnormalities. A women is born with all of the eggs she will ever have during a life time and they age as the women ages. Although, men can have children at whatever age they want, women cannot. About 10%-30% of all fertilized eggs within a female have the wrong number of chromosomes.
https://utswmed.org/medblog/age-matters-down-syndrome/
https://www.eurekalert.org/pub_releases/2021-02/uoz-ras022321.php
In February of 2021, Zurich University released an article “Reactivating Aging Stem Cells in the Brain”. The article explains new research about neurogenesis for aging neurons. The study focuses on patients with Alzheimer’s and on the hippocampus because of its involvement in memory. The article explains that there are harmful proteins located in the nuclei of neural stem cells. In a healthy brain, these proteins are unevenly distributed into two daughter cells during cell division to combat the deteriorating impact that it may have. As time goes on, this uneven distribution decreases as the proteins increase. The main protein considered in this is lamin B1. Lamin B1 decreases over time and is used in this study because of the possible involvement it may have in neuron growth and development. They found that after increasing lamin B1 in mice, stem cell division improved and there was new neuron growth. This is important because of the decreased ability our neurons have to multiply over time. These findings are intended for patients with Alzheimer’s and neurogenesis but could also lead us to activating neurons that have been negatively impacted by trauma or injury.