For the genetic disorder of Down syndrome answer the following questions: Gene l
ID: 66090 • Letter: F
Question
For the genetic disorder of Down syndrome answer the following questions: Gene locus on which chromosome: Type of disorder (autosomal, sex linked, dominant, recessive, aneuploidy?) Symptoms of the disorder Name of Normal Protein: Function of the Normal Protein: How is Mutant Protein Involved in the development of symptoms of the disorder? Write a genetics problem based on the disorder you have chosen Provide the solution to your problem Include text and/or a Punnett square table explaining your solution Include the appropriate probabilities.Explanation / Answer
1. chromosome 21
2. Trisomy 21
In 90% of Trisomy 21 cases, the additional chromosome comes from the mother's egg rather than the father's sperm. Down syndrome is the most common genetic disorder caused by a chromosomal abnormality. It affects 1 out of every 800 to 1,000 babies.
3.
Physical Symptoms:
4. SNX27 protein
5. Mice who were deficient in the SNX27 protein exhibited similar characteristics to mice with Down syndrome—namely, they had fewer glutamate receptors, which are important for learning and memory, the team reported in Nature Medicine on Sunday (March 24). The researchers also showed that in mice with Down syndrome, the protein is blocked by a molecule encoded on chromosome 21, and produced in excess in Down syndrome mice as a result of their trisomy. When the team supplemented SNX27 in the brains of mice with Down syndrome, they could see restoration of the glutamate receptors and improvements in memory deficits. “In Down's syndrome, we believe lack of SNX27 is at least partly to blame for developmental and cognitive defects,” senior author Huaxi Xu told BBC News.
6.
Although all children with Down syndrome have trisomy 21, most will not eventually develop leukemia, indicating that there other genetic processes involved. Mutations of the GATA-1 gene have been identified as an early event in AML and transient myeloid disorders observed in Down syndrome patients, but the existence of a similar unique mutation in Down-syndrome-related ALL has not yet been identified. However, the existence of a similar unique collaborating mutation in children with Down syndrome who develop ALL has been postulated.
To identify a possible mutation, Dr. Izraeli and an international team conducted a large mutational screening, using 81 diagnostic samples of B cell precursor Down-syndrome-related ALL, which was stored in the central laboratories of 9 European childhood ALL protocols.
The researchers identified a specific mutation in JAK2, which was present in 19.7% of Down-syndrome-related ALL patients, demonstrating that novel mutations of JAK2 are associated with trisomy 21 in almost one fifth of Down-syndrome-related ALL cases.
7. Most cases of Down syndrome result from trisomy 21, which means each cell in the body has three copies of chromosome 21 instead of the usual two copies.
Less commonly, Down syndrome occurs when part of chromosome 21 becomes attached (translocated) to another chromosome during the formation of reproductive cells (eggs and sperm) in a parent or very early in fetal development. Affected people have two normal copies of chromosome 21 plus extra material from chromosome 21 attached to another chromosome, resulting in three copies of genetic material from chromosome 21. Affected individuals with this genetic change are said to have translocation Down syndrome.
A very small percentage of people with Down syndrome have an extra copy of chromosome 21 in only some of the body's cells. In these people, the condition is called mosaic Down syndrome.
Researchers believe that having extra copies of genes on chromosome 21 disrupts the course of normal development, causing the characteristic features of Down syndrome and the increased risk of health problems associated with this condition.
8. People with Down syndrome are at a greater risk for a number of health problems and conditions than are those who do not have Down syndrome. Many of these associated conditions may require immediate care right after birth, occasional treatment throughout childhood and adolescence, or long-term treatments throughout life. For example, an infant with Down syndrome may need surgery a few days after birth to correct a heart defect; or a person with Down syndrome may have digestive problems that require a lifelong special diet.
Children, teens, and adults with Down syndrome also need the same regular medical care as those without the condition, from well-baby visits and routine vaccinations as infants to reproductive counseling and cardiovascular care later in life. Like other people, they also benefit from regular physical activity and social activities.