Case Study
Biology
Tay Sachs is an autosomal recessive disease. In order to exhibit the disease someone must be homozygous recessive. However, one can be a carrier of the disease and not show any symptoms. This is how the disease persists in populations and is passed from generation to generation. This disorder is neurodegenerative which means that the neurons in the brain deteriorate. In this case, deterioration is due to excess storage of the cell membrane glycolipid, GM2 ganglioside. The isoenzyme β-Hexosaminidase A (Hex A) hydrolyzes, or breaks down, GM2 (1). Mutations in the Hex A gene inhibits its ability to hydrolyze GM2 allowing for excess in the brain.
Tay Sachs is an autosomal recessive disease. In order to exhibit the disease someone must be homozygous recessive. However, one can be a carrier of the disease and not show any symptoms. This is how the disease persists in populations and is passed from generation to generation. This disorder is neurodegenerative which means that the neurons in the brain deteriorate. In this case, deterioration is due to excess storage of the cell membrane glycolipid, GM2 ganglioside. The isoenzyme β-Hexosaminidase A (Hex A) hydrolyzes, or breaks down, GM2 (1). Mutations in the Hex A gene inhibits its ability to hydrolyze GM2 allowing for excess in the brain.
Intro to couple:
Male and female both of Jewish ancestry. From previous research we know this means their risk of both being carriers is 1/900 (2). For this reason, the couple decides to get tested using DNA analysis. Results of the testing show that both are carriers of the disease.
What must their genotypes be?
Male and female both of Jewish ancestry. From previous research we know this means their risk of both being carriers is 1/900 (2). For this reason, the couple decides to get tested using DNA analysis. Results of the testing show that both are carriers of the disease.
What must their genotypes be?
What percent chance does an offspring have of being affected by Tay Sachs?
What do the tests look for in cells?
If a homozygous recessive offspring is produced, he or she will exhibit Tay Sachs disease. This offspring has inherited two mutated copies of the gene. Tay Sachs is coded for on chromosome 15.
What do the tests look for in cells?
If a homozygous recessive offspring is produced, he or she will exhibit Tay Sachs disease. This offspring has inherited two mutated copies of the gene. Tay Sachs is coded for on chromosome 15.
Works Cited:
(1,2) Sutton, V. Reid, MD. "Tay Sachs Disease: Screening and Counseling Families at Risk for Metabolic Disease." Obstetrics and Gynecology Clinics of North America 29.2 (2002): 287-96. Web. <http://www.sciencedirect.com.proxygw.wrlc.org/science/article/pii/S088985450100002X>.
Photo 1: http://commonhealth.wbur.org/2011/11/tay-sachs-human-trial
Photo 2: http://www.myhealthyfeeling.com/tay-sachs-disease-pictures-facts-symptoms-treatment/
Photo 3: http://019221f.netsolhost.com/carrierstats.shtml
Photo 4: http://isbbio2.wikispaces.com/TSCauses
(1,2) Sutton, V. Reid, MD. "Tay Sachs Disease: Screening and Counseling Families at Risk for Metabolic Disease." Obstetrics and Gynecology Clinics of North America 29.2 (2002): 287-96. Web. <http://www.sciencedirect.com.proxygw.wrlc.org/science/article/pii/S088985450100002X>.
Photo 1: http://commonhealth.wbur.org/2011/11/tay-sachs-human-trial
Photo 2: http://www.myhealthyfeeling.com/tay-sachs-disease-pictures-facts-symptoms-treatment/
Photo 3: http://019221f.netsolhost.com/carrierstats.shtml
Photo 4: http://isbbio2.wikispaces.com/TSCauses