Chapter 6 Autosomal Inheritance and Disorders

Chapter 6: Autosomal Inheritance and Disorders 1.Which syndrome or condition represents monosomy? C. Turner syndrome 2.Which autosomal condition or syndrome commonly features a cleft lip and palate? B. Cri du chat 3.Which description is the best example of “genomic imprinting”? C. There is a qualitative difference in some gene alleles based on whether they are inherited from the mother or the father. 4.Why does an embryo with a balanced translocation have the same chance for normal development that an embryo with a normal karyotype has? C. Although the location of the genetic material is abnormal with a balanced translocation, there are no missing or extra alleles. 5.How is a Robertsonian translocation different from a reciprocal translocation? D. Robertsonian translocations occur between whole acrocentric chromosomes, and reciprocal translocations occur between any two nonhomologous chromosomes. 6.Why does a person who has a deletion of the coding regions for five genes on one chromosome 15 have some manifestations or overt problems? B. He or she has only one copy of the gene alleles, which results in reduced function. 7.What is the most likely explanation for a baby boy to have Tay–Sachs disease when the child’s mother is not a carrier for the problem, but the father is a carrier? B. The mother’s normal gene allele is not expressed, and the father’s Tay–Sachs allele is expressed. 8.Which statement about partial deletions and duplications of autosomes is true? D. The incidence increases with advancing maternal or paternal age. 9.What is the best explanation for a person whose karyotype from blood cells shows nearly all cells to have trisomy 21 to have 10 clinical manifestations of Down syndrome and an above-average intelligence? D. The person has mosaicism of trisomy 21, with blood cells having a high proportion and neurons having a low proportion of cells, with three number 21 chromosomes. 10.Which reproductive consequence is possible for a man who has a 13;15 Robertsonian translocation when his wife has a normal karyotype? C. He has an increased risk for having a child born with either trisomy 13 or trisomy 15. 11.Why is Down syndrome the most common trisomy disorder seen among liveborn infants? A. The extra alleles from trisomies of larger chromosomes are embryo lethal. 12.What is the risk for a man who has Down syndrome to produce a child with Down syndrome with a woman who has a normal karyotype? D. 0% 13.Which chromosome is trisomic in Edward syndrome? B. 18 14.For a person who has any type of chromosomal abnormality, what factor(s) has/have the greatest impact on both physical and cognitive potential? C. Personal family environment and social interaction 15.Which statement regarding partial chromosomal deletions or duplications reflects the cause of manifestations? A. They result in either a triple dose of some gene alleles or a single dose of some alleles. 16.Which cancer type has an increased incidence among children with WAGR syndrome? D.N ephroblastoma 17.What is the risk for a woman who had a retinoblastoma in early childhood as a result of a partial deletion on one number 13 chromosome to have a child who also develops the disorder? B. 50% 18.Which feature of a 15q deletion is present in both Angelman syndrome and Prader–Willi syndrome? A. Light skin, eye, and hair coloring 19.Which factor has the greatest influence on the expression of a genetic disorder such as Prader–Willi syndrome or Angelman syndrome through the process of genomic imprinting? C. The gender of the parent transmitting the deletion 20.What is the best explanation of a child having the physical phenotype of Down syndrome but having a totally normal karyotype on chromosomal analysis of blood? A. Mosaicism of trisomy 21 in various tissues