A karyotype test can be performed in several ways, and can be done during. Feb 04, 2019 down syndrome ds or dns, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. Making a karyotype, an online activity from the university of utahs genetic science learning center. Trisomy 9, believed to be the 4th most common trisomy, has many long lived affected individuals but only in a form other than a full trisomy, such as trisomy 9p syndrome or mosaic trisomy 9. What notation would you used to characterize pacient bs karyotype. The website was created by university of arizonas biology project and provides the opportunities to create and analyse chromosomes while creating a karyotype. Although women of any age can have a child with down syndrome, the chance of having a child with this condition increases as a woman gets older. Its characterized by a variety of distinctive physical features, an increased risk of certain medical problems, and varying degrees of developmental and intellectual delays.
This excess genetic material, in the form of additional genes along chromosome 21, results in down syndrome. Down syndrome, a common chromosomal disease, is caused by trisomy of chromosome 21. Dec 14, 2017 mosaic down syndrome is a rare, less severe form of down syndrome. It was later determined that an extra partial or complete chromosome 21 results in the characteristics associated with down syndrome. All affected individuals experience cognitive delays, but the intellectual disability is usually mild to moderate. Rapid testing versus karyotyping in downs syndrome. Although the pediatricians initial contact with the child is usually during infancy, occasionally the pregnant woman who has been given the prenatal diagnosis of down syndrome will be referred for counseling. Transcription disorders disorders with meiosis monosomies and trisomies how to construct karyotype charts spotting disorders with karyotype charts down, turner, klinefelter, edward, patau, triplox and jacobs disorders.
Discuss chromosomes as a means of organising dna and how genetic disease can be caused through incorrect numbers of chromosomes e. Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on chromosome 21, either in whole trisomy 21 or part such as due to translocations. We explain the condition, its cause, symptoms, and how to diagnose it. This is one of the most common causes of mental deficiencies. Mosaic down syndrome is a rare, less severe form of down syndrome. Instead of the usual 46 chromosomes present in each cell, lejeune observed 47 in the cells of individuals with down syndrome. Disorder name description of disorder subject circle c, d, or e symptoms list 12 from diagnosis down syndrome extra chromosome 21 c d e klinefelter syndrome extra x in male xxy c d e turner. A picture of all the chromosomes in a cell arranged in pairs. People with down syndrome may have a variety of birth defects.
The last becomes a translocation carrier, like the parent. Rapid testing versus karyotyping in downs syndrome screening. How does subject cs karyotype differ from a normal karyotype. If the karyotype is abnormal, circle the abnormality in the karyotype. A lab technician can create a karyotype by collecting a sample of cells from an individual. Karyotype analysis activity the american biology teacher. Individuals who have down syndrome have unique facial features and physical features, certain medical findings such as heart defects, gastrointestinal problems, etc. Then have students cut out and complete the karyotype ensure there is a mixture of the three patient karyotypes across the class. Karyotyping activity this exercise is a simulation of human karyotyping using digital images of chromosomes from actual human genetic studies. Down syndrome, also known as trisomy 21, is a genetic disorder that occurs when a person has a full or partial extra copy of chromosome 21. Then explain what is wrong with the karyotype, and where the abnormality is located specifically on the chromosome. Combination of water and land exercise is an effective strategy to improve daily activities in down syndrome children. Students then diagnose the chromosomal aneuploidy based on the karyotype, list the symptoms associated with the disorder, and discuss the implications of the diagnosis. Down syndrome is correlated with age of mother but can also be the result of nondisjunction of the fathers chromosome 21.
After a positive screening, women are offered prenatal foetus karyotyping, the gold standard. It was noted that combination of exercise and aqua therapy showed significant improvement in many motor parameters in downs syndrome children. Trisomy 21, commonly referred to as down syndrome, is caused by an additional copy of the 21st chromosome that typically results from a nondisjunction event during gametogenesis. The second, combined with a normal gamete from the other parent, gives rise to a typical child.
These guidelines are designed to assist the pediatrician in caring for the child in whom the diagnosis of down syndrome has been confirmed by karyotype. What notation would you used to characterize pacient cs karyotype. Next to each karyotype, identify it as either normal or abnormal. This product offered by spyglass biology contains a single worksheet about disorders caused by nondisjunction as well as reading karyotypes to identify the disorders. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Introduction mendels model of inheritance is the basis for modern genetics. Start studying karyotyping and down s syndrome lc 1. Print the three patient karyotypes attached as a pdf. This results in a number of characteristic features, such as short. This activity is perfect for group and whole class discussion.
Karyotype analysis of human chromosome easybiologyclass. Start studying karyotyping and downs syndrome lc 1. Student work ol karyotype activity the university of arizonas biology project provides an amazing activity for students to work with real data to reinforce the content of todays. Health supervision for children with down syndrome american. In this activity, you will use a computer model to look at chromosomes and prepare a karyotype. Karyotype curiosities determining different karyotypes when geneticists want to look at a persons chromosomes, they make a karyotype. Click on karyotyping under human biology and read the introduction page. A case of down syndrome with 45 chromosomes was presented. Karyotype and idiogram ppt karyotype, idiogram and its significance ppt what is karyotype. Down syndrome is the most common chromosome abnormality in humans. Chromosome analysis national dna day april 25, 2005.
The effects of the extra copy varies greatly from individual to individual, depending on the extent of the extra copy, genetic background, environmental factors, and random chance. Down syndrome with 45 chromosomes journal of human genetics. Karyotype of the propositus was determined as 45, xy. When finished, use the print screen option to copy your karyotype into a word processing document or image editor. Trisomy 21 down syndrome z individuals with down syndrome have a typical facial appearance z all have some degree of mental retardation, but for most it is mild or moderate z can learn to read, write, do some math, and live daytoday with minimal assistance from others z others require a lot of attention and care z. What type of cell samples are used for karyotyping. This exercise is a simulation of human karyotyping using digital images of chromosomes from actual human genetic studies.
This is the fifth report of down syndrome with 45 chromosomes. Down syndrome is usually identified at birth by physical traits. Down syndrome is a chromosomal condition that is associated with intellectual disability, a characteristic facial appearance, and weak muscle tone hypotonia in infancy. These syndromes therefore may have a genetic basis. Down syndrome ds or dns, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. While the karyotype of a typical person shows 23 pairs of chromosomes for a total of 46, the karyotype of a person with down syndrome shows an additional 21st chromosome, resulting in a total number of 47. The 5 disorders are down syndrome, klinefelters, xyy syndrome, turners syndrome, and. This ordering and pairing of chromosomes is called a karyotype. The extra 21st chromosome is detected by using a procedure called a karyotype. Karyotyping activity with case histories from the university of arizonas biology project.
Translocation down syndrome is often referred to as familial down syndrome. Age of diagnosis was determined using date of receipt. Karyotype karyotype of a person with down syndrome the chromosomal basis of down syndrome to understand why down syndrome occurs, the structure and function of the human chromosome must be understood. Accuracy of the clinical diagnosis of down syndrome. Trisomy 21 down syndrome is the most common cause of genetic mental retardation, occurring in one in 700 live births. Reliable molecular methods for rapid aneuploidy diagnosis. Trisomy 21 is a prototypical genetic condition in which characteristic facial features fig. Use guided inquiry to analyze 7 human karyotypes and match with descriptions on a chart.
The karyotype activity consists of two sets of chr omosomes, mom s chromosomal contribution and dads chromosomal contribution. Karyotyping requests for a clinical diagnosis of down syndrome were also identified. Sep 30, 2015 the students can then take that information and research it online or at a library to find the syndrome s name and symptoms long answer set. Down syndrome can be diagnosed by physical features in most cases, and is confirmed by a karyotype usually done on a blood sample. This activity is targeted at undergraduates in a nonmajors genetics course.
Genesis, a database located in the department of medical genetics, was used to identify the number of down syndrome karyotypes including trisomy, translocation, and mosaic sample variants. The purpose of karyotype analysis is to look at the gross anatomical structures of the chromosomes of an individual. This important model can be broken down into four main ideas. A karyotype is a picture of chromosomes that have been organized in homologous pairs from. The incidence of this syndrome is 1100,000 live births. Diagnosing chromosome disorders, haspi medical biology lab 17 names.
It occurs in about one per 1,000 babies born each year. Syndrome trisomy 21 is a genetic disorder caused by the presence of an extra 21st chromosome. The students worksheets are five pages long since they include an introduction in each set. With advanced medical treatments, the average life span of an individual with down syndrome is now about 50 years. One way to determine the underlying cause of a syndrome with a genetic basis is to produce a karyotype and then look for chromosomal abnormalities that may explain it. You will be arranging chromosomes into a completed karyotype, and interpreting your findings just as if you were working in a genetic analysis program at a hospital or clinic. About 5,300 babies with down syndrome are born in the united states each year, and approximately 200,000 people in this country have the condition. Ninth grade lesson creating karyotypes betterlesson. The students can then take that information and research it online or at a library to find the syndromes name and symptoms long answer set. It is usually associated with physical growth delays, mild to moderate intellectual disability, and characteristic facial features. What notation would you used to characterize pacient as karyotype. In this lesson, students will analyze the effect of environmental and hereditary factors on fetal development, including prenatal brain development. A down syndrome karyotype is a genetic screening tool that identifies the presence of a chromosome 21 abnormality.
Individuals with down syndrome are more likely to survive through birth and beyond as compared to other trisomy disorders. How do two physically healthy parents produce a child with down syndrome and a second child with cri du chat syndrome. The 5 disorders are down syndrome, klinefelters, xyy syndrome, turners syndrome, and trisomy x. In individuals with down syndrome, however, the cells usually contain 47, not 46, chromosomes. The human male determines the sex of all of his offspring. Analysis of a normal karyotype observe the karyotype below. You will diagnose patients for abnormalities and learn the correct notation for characterizing karyotypes. Chromosome analysis national human genome research. Sep 15, 2010 in all, 80% of antenatal karyotypes are generated by down s syndrome screening programmes dssp. The third leads to a translocation down syndrome child. Such changes, primarily the result of nondisjunction or translocation, are so severe that the pregnancy ends in miscarriage or fertilization does not occur at all. These features may be present in babies who do not have down syndrome, so a karyotype chromosomal analysis is done to make a diagnosis. Choose from 500 different sets of karyotype flashcards on quizlet. In all, 80% of antenatal karyotypes are generated by downs syndrome screening programmes dssp.
Usually, this is done by a genetic counselor trying to determine if the person has a genetic abnormality. Occasionally chromosomal material is lost or rearranged during the formation of gametes or during cell division of the early embryo. Testing for down syndrome is offered as a part of routine antenatal care for women in most developed nations, and has been increasingly introduced in developing countries. The test results can show whether or not your baby has down syndrome, trisomy, trisomy 18, or other genetic problems. Analysis questions 1 how many autosomes any chromosome that that is not a sex chromosome are in a normal human karyotype. This classroom activity is based on a constructivist learning design and engages students in physically constructing a karyotype of three mock patients.
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