APY248 Exam 2 Review

APY248 Exam 2 Review - Autosomal Dominant Diseases Criteria...

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Autosomal Dominant Diseases Criteria for/Inheritance pattern Person only needs to get gene from one parent to inherit disease (non sex chromosome) Ex: out of 4 children, 2 will inherit the disease The children who did not inherit the disease will not develop or pass it on (not carriers) Huntington Disease Neurodegenerative genetic disorder Nerve cells in the brain waste away, causing muscle spasms throughout the body Causes – by genetic defect on the HTT gene on the short arm of chromosome number 4, Causes a part of the DNA (CAG) to repeat many more times than its supposed to It normally repeats 10-35 times, but with this mutated gene it repeats 36-120 times. As the gene is passed down to generations, the number of repeats expands More repeats equal higher chance of early onset. CAG (cytosine-adenine-guanine) repeats lead to a continuous polyglutamine tract, which is a portion of a protein consisting of several glutanine units. A sequence of 36 or more repeated glutanine units result in a protein with different characteristics (mHTT) and increases decay in certain types of neurons. Symptoms – uncoordinated and jerky body movements, decline in mental abilities, behavioral and psychiatric problems, physical abilities gradually decline until coordinated movement becomes difficult, mental abilities generally decline to dementia Treatment – no treatment for it Once it’s onset, life expectancy is 15 years Passed down in families through generations LOOK AT NOTES BOTTOM PAGE Marfan Syndrome genetic disorder of connective tissues that causes mutations in the heart valves and aorta Symptoms – usually abnormally tall, moderate curvature of the spine, aorta problems, dislocated limbs, and eyes Cause - mutations in the FBN1 gene cause Marfan syndrome FBN1 provides instructions for making the protein fibrillin1.
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Fibrillin1 binds itself and other proteins and molecules to produce threadlike filaments called microfibrils, which become part of the fibers that provide strength and flexibility to connective tissue They also hold molecules called growth factors and release them at appropriate times to control growth and repair tissues and organs. Fibrillin also helps give the aorta strength and elasticity. Mutation in this gene weakens the aorta wall and suspensory tissue in eyes and limbs. Mutation in FBN1 reduces amount/quality of fibrillin1 that is available to form microfibrils. Older fathers are more likely to pass down MS because his sex cells have gone through many mitotic divisions and have had many opportunities to gather defects. Achondroplasia An inherited skeletal disorder beginning before birth cartilage is converted to bone resulting in dwarfism it is a form of short limbed dwarfism, average 4 foot stature Having two copies of this gene from both parents is deathly Homozygous parents will give birth to offspring who is severely effected; usually die
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APY248 Exam 2 Review - Autosomal Dominant Diseases Criteria...

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