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Since the gene is found on the X chromosome, it can only be given to offspring by the mother’s DNA. Sex-linked traits can only be expressed if there is not another X chromosome to counter the mutated gene with its normal gene. This puts males (have X and Y chromosomes) at a huge disadvantage because they do not have another X chromosome like females (have two X chromosomes) do. Males with mothers who are carriers of the mutated gene have a fifty percent chance of inheriting disease because there are two X chromosomes (one has the mutated gene) in which they can be given. This is why sex-linked traits, such as the gene for Huntington’s disease, most often affect males. Although females of mothers with the mutated gene are less likely to be affected by the mutated gene, they can be carriers of the mutated gene and pass it on to their offspring.
Although there is no cure for Huntington’s disease, scientists have made a lot of progress towards finding a cure. In 1983, a scientist named Nancy Wexler and others discovered that the gene for Huntington’s disease was located on the short arm of chromosome 4. Almost a decade later they found that a codon with the nucleotides CAG repeated multiple times in people carrying Huntington’s disease. A normal person who is not carrying the mutated gene has anywhere between 10 and 35 CAG codons. They …show more content…
This extra copy is created when a pair of chromosome 21 fails to separate during egg formation. The embryo is created with three copies of chromosome 21 (“Down Syndrome” Genetic Science Learning Center, 2006). This extra copy of chromosome 21 may cause more of certain proteins to be produced than normal. Scientists believe that the greater amounts of these proteins could be responsible for the wide range of symptoms that people with Down syndrome experience. About 1 out of every 800 to 1000 babies has Down …show more content…
Although many of the symptoms are similar from one person to another, they are never the same because this disorder is caused by a unique abnormality. Some of the common physical symptoms include a smaller skull, underdeveloped nasal bone at birth, smaller ears, enlarged tongue, shorter and broader neck, and absence of one of the 12 ribs. Typical mental characteristics include troubles with gross motor skills, language, and speech. People with Down syndrome also may experience heart problems, gastrointestinal disorders, orthopedic problems, hearing problems, eye problems, and Alzheimer’s disease (Tingey, 34).
Right now, there are no cures for Down syndrome, but scientists from Stanford University are now finding that gene therapy may be possible within the next ten years. They are currently working on identifying the 235 genes on chromosome 21 and finding out what symptoms each gene causes. Stanford Scientists are thinking that drugs can be developed to “turn off” the third copy of chromosome 21, which would make the body produce a normal amount of each protein and hopefully eliminate the symptoms of Down syndrome (Shari Roan,
Although there is no cure for Huntington’s disease, scientists have made a lot of progress towards finding a cure. In 1983, a scientist named Nancy Wexler and others discovered that the gene for Huntington’s disease was located on the short arm of chromosome 4. Almost a decade later they found that a codon with the nucleotides CAG repeated multiple times in people carrying Huntington’s disease. A normal person who is not carrying the mutated gene has anywhere between 10 and 35 CAG codons. They …show more content…
This extra copy is created when a pair of chromosome 21 fails to separate during egg formation. The embryo is created with three copies of chromosome 21 (“Down Syndrome” Genetic Science Learning Center, 2006). This extra copy of chromosome 21 may cause more of certain proteins to be produced than normal. Scientists believe that the greater amounts of these proteins could be responsible for the wide range of symptoms that people with Down syndrome experience. About 1 out of every 800 to 1000 babies has Down …show more content…
Although many of the symptoms are similar from one person to another, they are never the same because this disorder is caused by a unique abnormality. Some of the common physical symptoms include a smaller skull, underdeveloped nasal bone at birth, smaller ears, enlarged tongue, shorter and broader neck, and absence of one of the 12 ribs. Typical mental characteristics include troubles with gross motor skills, language, and speech. People with Down syndrome also may experience heart problems, gastrointestinal disorders, orthopedic problems, hearing problems, eye problems, and Alzheimer’s disease (Tingey, 34).
Right now, there are no cures for Down syndrome, but scientists from Stanford University are now finding that gene therapy may be possible within the next ten years. They are currently working on identifying the 235 genes on chromosome 21 and finding out what symptoms each gene causes. Stanford Scientists are thinking that drugs can be developed to “turn off” the third copy of chromosome 21, which would make the body produce a normal amount of each protein and hopefully eliminate the symptoms of Down syndrome (Shari Roan,