Trisomy 18-Edwards Syndrome
Clinical Laboratory Genetics
MLS 4133 21368
Fall 2016
Taja Colbert Abstract
This research explains the genetic disorder of Trisomy 18, the three forms associated with the disordered and how they occur. Symptoms and characteristics of the disorder are described, as well as several methods of diagnosis, possible treatment and the probable outcomes of the disease.
First describe in 1960, Trisomy 18, also known as Edwards syndrome, is a severe genetic disorder resulting from meiotic disjunction, which is an error in cell division similar to Down syndrome. Meaning that extra material from chromosome 18 is made, creating three copies instead of the normal two, this abnormality is a random occurrence and is
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Seen approximately 1 in 2,500 pregnancies in the United States, many ending in the second and third trimesters due to intrauterine growth retardation. Only 1 in 6,000 live births is documented, with the majority being girls who rarely survive the first weeks of life. Infants with this condition, are generally admitted immediately to NICU due to low birth weight and the likelihood of multiple organ abnormalities. The baby, depending on severity, may have abnormal features including an undeveloped skull with a small jaw and mouth, cleft lip and palate, overlapping fingers with underdeveloped thumbs, low-set ears, rocker bottom feet, protrusion of sternum and ribs, exomphalos, as well as mental delays. These abnormalities introduce more problems and complication for the child, such as feeding issues, breathing problems, hernias, as well as recurrent infections. The future for these children generally requires a dependency on a caretaker for daily …show more content…
The fetus may measure under expected weight, and with later ultrasounds, physical abnormalities may be seen. The use of an ultrasound is not a full proof method of diagnosis for trisomy 18. During the end of the first trimester, pregnant mothers are given the option of prenatal screening to assess the fetal risk of certain chromosomal abnormalities, including trisomy 18. This testing referred to as combined test, combines results from the mother’s blood and the ultrasound results. If results suggest a higher risk probability, a later more conclusive test will be scheduled. During the 15th to 18th week of pregnancy, an amniocentesis or chorionic villus can be performed to have a detailed analysis of the fetal chromosomal material which will show any abnormalities in their karyotype. There is a slight risk with both procedures of injury of the fetus or possible miscarriage. Newer testing has been developed as “non-invasive prenatal diagnosis,” which involves extracting fetal DNA from the mother’s blood sample. After birth, diagnosis is suspected based on physical attributes of the infant. As with before birth, blood testing for chromosome analysis is used for confirmation
During pregnancy an echocardiogram of the fetus can be done to produce images of the heart by sending ultrasonic sound waves to the vital organ. These sound waves create an image for the physician to analyze the babies heart function, structure sizes, and blood flow. A positive diagnosis before birth has shown to improve chances of survival, and will allow for appropriate care to be readily available at birth. If a baby is born without being diagnosed with the heart defect, some symptoms previous noted such as low oxygen levels can be suggestive of hypoplastic left heart syndrome. The baby may not display any symptoms or signs for hours after birth because of the openings allowing for blood to be pumped to the rest of the body. However, listening to the babies heart can revel a murmur indicating an irregular flow of blood in the heart. If a murmur is heard, or signs of the defect are observed, diagnostic tests will be ordered and performed. An echocardiogram is still the go-to test once the baby is born to evaluate the heart. The echocardiogram will diagnose the newborn, by revealing the underdeveloped left ventricle, mitral and aortic valve, and the ascending aorta commonly seen in
Twin studies have been used to distinguish between genetic and environmental factors for many disorders in the general population including ectodermal dysplasia, Ellis-van Creveld, and anencephaly. This review focuses on genetic disorders affecting monozygotic, dizygotic, and conjoined twins to gain a better understanding of them. Many studies focus on twins because they have a nearly identical genome, which eliminates environmental factors. In case studies, the concordance rates in monozygotic twins have supported that certain disorders were caused by genetics and not the environment. The discordant values in twins will also be evaluated briefly. Twinning studies have also shown linkages between specific disorders and the genes responsible for them. Knowing the location of these genes allows patients to be treated quickly and efficiently. This paper will discuss the possible causes of twinning and the various methods of identifying abnormalities in twins. These methods also allow preventive measures against the rise of birth defects during prenatal development. Epigenetics in twins is also viewed through the perspective of effects on them. Treatments for genetic disorders in twins are reviewed, ranging from the restoration of malformed teeth to the separation of conjoined twins. Support groups for twins in treatment, and their families are also briefly reviewed.
The disease Angelman Syndrome, named after the physician Harry Angelman, was first diagnosed in 1965. It is now known that the disease results from the loss of function of UBE3A, a gene. One is normally inherited from each parent. The copy inherited from the mother is active in certain areas of the brain. If this copy of the gene UBE3A is lost due to chromosomal change or gene mutation, the lost gene will not have active copies in parts of the brain. A majority (70%) of Angelman syndrome cases happen when a segment of the maternal chromosome 15 is lost or destroyed. A minority of the disease is caused by a mutation or loss of function of the mother’s copy of the UBE3A gene. The majority of cases result from uniparental disomy, which is when the son or daughter inherits two copies of chromosome 15 from his or her father. Translocation, or chromosomal rearrangement, can also cause the disease. Most cases of this disease are not inherited, instead are a result of deletion in the maternal chromosome 15. Across 1. 2 copies of chromosome 15 are inherited from the father Down 1 Person who first diagnosed this disease 2 Disease the magazine is about 3 A gene 4 a minority of this disease is caused by this 5 Chromosomal rearrangement DISEASE BACKGROUND PAGE 1
Millie refers to Romans 8:28. She says that she believes God does not put anything in our lives that does not have a purpose. She even believes that to be true with her Trichotillomania. Millie decided to search for the reason that God put Trichotillomania into her life. “The Lord showed me that I needed to give trichotillomania to Him. He would then be the One to help get me through my ups and downs. He gave me the strength that I needed to face life and handle my problems” (Mason 2008). Once Millie came to this realization she found that she no longer need Trichotillomania to be her friend in order to lift her moods or help her relax. In fact, she no longer needed the hurtful act at all in her life.
The child that I tested will be referred to as K.L. I tested her on April 14th 2016. K.L. is 2 years old, with her exact age being 2 years 9 months and 14 days. I called and asked her mother if she would mind dropping K.L. off with me for a few hours so I could perform the test, and then pick her back up after the test was complete. This test more accurate when the caregiver is not present. K.L. has a step sister and a baby brother on the way. She has always been in the daycare setting, because her grandmother is a provider. K.L. was delivered full term via planned cesarean section due to her mother’s small pelvis. There was no complications during this pregnancy. K.L. weighted 8 lbs. 4 oz. and was 20 ½ inches long at birth, now weighting in at ...
While pregnancies with a trisomy (a baby which has receive an extra chromosome) or a monosomy (have a missing chromosome) may go to full-term and result in the birth of a child with health problems, it is also possible that the pregnancy may miscarry, or that the baby is stillborn, because of the chromosome abnormality. In studies of first trimester miscarriages, about 60 percent (or more) are chromosomally abnormal. In studies of babies who are stillborn, 5 to 10 percent have a chromosome
The Autonomic Nervous System is responsible for the functions of the body that are not thought about to control. When this system dysfunctions, it can cause havoc on the human body. One example of this would be Dysautonomia. Dysautonomia is a rare but serious disease that affects the autonomic nervous system, has many symptoms, and offers few treatment options.
The type of mutation that occurs in Down syndrome is aneuploidy that is the irregular number of chromosomes in a cell. The most common of the three is the trisomy 21 that occurs in about 90% of people with the disorder. In this factor the human is given three copies of the chromosome 21 instead of the common two copies. This occurs due to the complications of the cell division in the process of the egg or sperm. The next case is mosaic which happen when there are inequality of cells with three copies of chromosome 21 and others with the original two copies. Mosaic appears when there is an unexpected cell division after fertilization. The last and the rarest form is translocation and that happens while the chromosome 21 in cell division is broken off and attached to another chromosome. Since the disorder is unexpected there are numerous amounts of risk factors that are possible based on the severity of the person.
Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 21. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 21 in each of the body's cells.
The desire to have a "normal" child is held by every parent and only now are we beginning to have the ability to select for that child. In preparation to receiving genetic testing, the parents are required to meet with a genetic counselor. A detailed description of the testing methods are reviewed with the couple as well as the risks which are involved with each. Upon an understanding of the procedures, the counselor discusses the many possible outcomes which could be the result of the diagnosis. Finally, before any tests are performed, anxieties from either of the parents are addressed as well as the psychological well-being of the parents.
When someone has three chromosomes in chromosome 21, it means you have Down syndrome. I know that the gene mutation in the picture is Down syndrome because when you have three chromosomes present, people tend to use the term "trisomy," which is also known as Down syndrome. Down syndrome a genetic disorder that affects not only the child or person with it, but also everyone else. Down syndrome is a mental and physical genetic disorder that is very rough on someone.
He published a comprehensive medical description of the syndrome. It was not until 1959, that it became clear the syndrome was due to lack of sex chromosome material. Turner's Syndrome is a rare chromosomal disorder that affects one in approximately 2,500 females. Females normally have two X-chromosomes. However, in those with Turner's Syndrome, one X chromosome is absent or is damaged.
Prenatal genetic screening in particular is a polarizing topic of discussion, more specifically, preimplantation genetic diagnosis (PGD). PGD is one of the two techniques commonly used to genetically screen embryos in vitro; it is usually done at the eight-cell stage of division. PGD is most often performed when there is the risk that one or both parents carry disease-causing mutations. It is extensively used by high-risk individuals trying to conceive babes who will be free of particular mutations. PGD can test for over 50 genetic conditions and even allows for sex selection if there are underlying gender-associated medical conditions. When the results are satisfactory, the selected embryo is implanted into the mother’s uterus. While a controversial technique, preimplantation genetic diagnosis is one example of some of the good genetic testing can do, more benefits will be furthe...
Conjoined twins, more commonly known as Siamese twins because of Chang and Eng Bunker, are considered extremely rare among populations. According to the University of Maryland Medical Center, births of conjoined twins occur only once out of every 200, 000 births. Twins become conjoined when an embryo starts to divide but fails to complete the process. While the twins become a single entity, they are considered separate individuals. However, most conjoined twins do not survive after birth and when they do they tend to have problems with malformed organs that are shared. The research by the University of Maryland Medical Center concludes that the overall survival rate of these conjoined twins is somewhere between 5 and 25 percent. With that being said, conjoined twins are often viewed as curiosities and a rare occurrence in our society in general.