Concept explainers
To review:
To discuss Homocystinuria and its specialized diet based treatment.
Introduction:
Homocystinuria is an inherited disorder in which the body is unable to process certain amino acids properly due to a deficiency of cystathionine beta synthase. Homocystinuria is a disorder of methionine
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Genetic Analysis: An Integrated Approach (3rd Edition)
- Analysis of Autosomal Recessive and Dominant Traits Describe the primary gene or protein defect and the resulting phenotype for the following diseases: a. cystic fibrosis b. Marfan syndromearrow_forwardMike was referred for genetic counseling because he was concerned about his extensive family history of colon cancer. That family history was highly suggestive of hereditary nonpolyposis colon cancer (HNPCC). This predisposition is inherited as an autosomal dominant trait, and those who carry the mutant allele have a 75% chance of developing colon cancer by age 65. Mike was counseled about the inheritance of this condition, the associated cancers, and the possibility of genetic testing (on an affected family member). Mikes aunt elected to be tested for one of the genes that may be altered in this condition and discovered that she did have an altered MSH2 gene. Other family members are in the process of being tested for this mutation. Once a family member is tested for the mutant allele, is it hard for other family members to remain unaware of their own fate, even if they did not want this information? How could family dynamics help or hurt this situation?arrow_forwardAchondroplasia is a rare dominant autosomal defect resulting in dwarfism. The unaffected brother of an individual with achondroplasia is seeking counsel on the likelihood of his being a carrier of the mutant allele. What is the probability that the unaffected client is carrying the achondroplasia allele?arrow_forward
- Mike was referred for genetic counseling because he was concerned about his extensive family history of colon cancer. That family history was highly suggestive of hereditary nonpolyposis colon cancer (HNPCC). This predisposition is inherited as an autosomal dominant trait, and those who carry the mutant allele have a 75% chance of developing colon cancer by age 65. Mike was counseled about the inheritance of this condition, the associated cancers, and the possibility of genetic testing (on an affected family member). Mikes aunt elected to be tested for one of the genes that may be altered in this condition and discovered that she did have an altered MSH2 gene. Other family members are in the process of being tested for this mutation. Is colon cancer treatable? What are the common treatments, and how effective are they?arrow_forwardMike was referred for genetic counseling because he was concerned about his extensive family history of colon cancer. That family history was highly suggestive of hereditary nonpolyposis colon cancer (HNPCC). This predisposition is inherited as an autosomal dominant trait, and those who carry the mutant allele have a 75% chance of developing colon cancer by age 65. Mike was counseled about the inheritance of this condition, the associated cancers, and the possibility of genetic testing (on an affected family member). Mikes aunt elected to be tested for one of the genes that may be altered in this condition and discovered that she did have an altered MSH2 gene. Other family members are in the process of being tested for this mutation. Seventy-five percent of people who carry the mutant allele will get colon cancer by age 65. This is an example of incomplete penetrance. What could cause this?arrow_forwardFragile-X syndrome causes the most common form of inherited intellectual disability. What is the chromosomal abnormality associated with this disorder? What is the phenotype of this disorder?arrow_forward
- Jekyll-Hyde Afflicted Spider Curse Afflicted Jekyll-Hyde/Spider Curse I O Human 1 II 1 III 4. Jekyll-Hyde disease is characterized by transformation into an unfeeling, aggressive, alter ego at night. While the "Spider Curse" is a disease that causes affected individuals to grow extra arms and extra eyes during a full moon. The genes responsible for these diseases sort independently and both traits run in one family. Based on the above pedigree answer the following questions: What is the mode of inheritance for Jekyll-Hyde disease? (Hint: look at individuals III-1 & III-3) O a. Autosomal Dominant O b. Autosomal Recessive O c. X-Linked Dominant O d. X-linked Recessive What evidence supports your hypothesis? Give at least 2 pieces of information from the pedigree that support your answer to 3a. Answer: 2. 3. 2. 2.arrow_forwardA couple are both phenotypically normal but their son suffers from hemophilla, a sex linked recessive disorder. What fraction of their children are likely to suffer from hemophilia. what fraction are likely to be carriers.arrow_forwardGenetic disorders Complete the following statements to describe several genetic disorders and their symptoms. Choices can be used more than once. The disorder called causes blue-colored skin, sickle-cell disease osteogenesis imperfecta The disorder called that leads to weakened, brittle bones. causes defective collagen methemoglobinemia autosomal dominant The disorder called causes abnormally thick mucus in the bronchial tubes and pancreatic ducts. autosomal recessive The disorder called leads to progressive cystic fibrosis degeneration of neurons in the brain. alkaptonuria The disorder called causes urine to be black. Huntington disease acer %23 24 & 4 8. 9. e y u < 6arrow_forward
- Genetic Inheritance Patterms Retinitis pigmnentosa (RP) can be autosomal recessive, autosomal dominant, or x-linked. Apparently the dominant forms are often less severe. Eric's form of RP is Usher's Syndrome, which is an autosomal recessive inheritance (i.e., you must get a copy of the defective gene from your Mom and one from your Dad). Autosomal means it is not carried on one of the chromosomes that determines sex. Usher's Type II is recessive, so for Eric this means that both his Mom and Dad are carriers of this condition. His brother, Dirk, does not have any symptoms of RP. Question below - short answer approach Imagine you are a genetics counselor, and Dirk, Erik's brother, comes in to see you. Based on his parents, what are Dirk's possible genotypes for RP? What advice would you give Dirk about the chances of Dirk's children having retinitis pigmentosa if his wife is not a carrier? How would your advice change if his wife fully has the disease? Describe all the possibilities,…arrow_forwardExplain the genetic alterations resulting in chromosomal aberrations and their relationship to disease processes such as trisomy 21 and Philadelphia-chromosome linked chronic myelocytic leukemia.arrow_forwardSickle cell anemia is an autosomal recessive genetic disorder. Because individuals affected bysickle cell anemia have defective hemoglobin proteins, their blood cannot transport oxygenproperly. There appears to be a relationship between the incidence of malaria and sickle cellanemia. Individuals with sickle cell anemia and carriers of the sickle cell allele have someresistance to malaria. Malaria is caused by the parasite Plasmodium and is transmitted amonghumans by mosquitoes.4. If scientists are successful in reducing significantly or eliminating malaria, the best predictionfor what will happen to the allele for sickle cell anemia in the population is that it willa. not be affected by the elimination of malariab. increase as its selective advantage is increasedc. be reduced as its selective advantage is decreasedd. disappear quickly as its selective advantage is increasedarrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning