Concept explainers
To determine: The treatment options for adenosine deaminase (ADA)-deficient severe combined immunodeficiency disease (SCID).
Introduction: Mr. and Mrs. J were referred to a clinical geneticist because their 6-month-old daughter was not growing appropriately. After the examination, the doctor observed that their daughter had a constant cough, wheeze, and extensive yeast infection. The doctor also took a blood test and determined that their daughter has suffered from SCID. It was also found that their daughter had inherited mutant allele for SCID from the parents.
Explanation of Solution
According to the case study, both the parents have the heterozygous mutant allele for ADA deficiency. The daughter has received both the mutant alleles from both father and mother and has become homozygous for the condition. ADA-deficient SCID is an immunodeficiency disorder. This condition causes a reduction in the synthesis of immune cells. In the absence of immune cells, the person would become immunocompromised. A person with ADA-SCID would become susceptible to infections. The possible treatment of this disease can be done by medicating the person with immune-modulating drugs.
Gene therapy is also a good option for the treatment of ADA-SCID. Using gene therapy, the gene of adenosine deaminase deficiency is replaced with normal genes. This would stimulate the immune system and improve the condition of the patient. However, the success rate of gene therapy is very low. In order to prevent the patient from infections, the patient must be kept in a sterile environment. However, there is no appropriate treatment for ADA-SCID that can cure this disease.
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Chapter 17 Solutions
Human Heredity: Principles and Issues
- The Joneses were referred to a clinical geneticist because their 6-month-old daughter was failing to grow adequately and was having recurrent infections. The geneticist took a detailed family history (which was uninformative) and a medical history of their daughter. He discovered that their daughter had a history of a constant cough and wheeze that was becoming progressively worse, had difficulty gaining weight (failure to thrive), and had an extensive history of yeast infection (thrush) in her mouth. The geneticist did a simple blood test to check their daughters white blood count and determined that she had severe combined immunodeficiency (SCID). The geneticist explained that SCID is an immune deficiency that causes a marked susceptibility to infections. The defining characteristic is usually a severe defect in both the T- and B-lymphocyte systems. This results in one or more infections within the first few months of life that are serious and may even be life-threatening. Based on the family history, it was possible that their daughter had inherited a mutant allele from each of them and therefore was homozygous for a gene that causes SCID. If so, each time the Joneses had a child, there would be a 25% chance that the child would have SCID. Prenatal testing is available to determine whether the developing fetus has SCID. If the Joneses want to be certain that their next child will not have SCID, what types of reproductive options do you think they have?arrow_forwardYesterday, when Daniel was showering after a basketball game in the gym, one of his friends asked, “Have you always had that big brown thing on your back?” Looking in the mirror, Daniel saw a large, dark brown, irregularly shaped mole. He checked in with a physician at the health center. She told him, “It’s probably just a large mole, but we should do a biopsy to find out for sure.” What genetic differences would you expect the pathology lab to find between a malignant tumor and an ordinary mole?arrow_forwardA proband female with an unidentified disease seeks the advice of a genetic counselor before starting a family. Based on the following data, the counselor constructs a pedigree encompassing three generations: (1) The maternal grandfather of the proband has the disease. (2) The mother of the proband is unaffected and is the youngest of five children, the three oldest being male. (3) The proband has an affected older sister, but the youngest siblings are unaffected twins (boy and girl). (4) All the individuals who have the disease have been revealed. Duplicate the counselors featarrow_forward
- Phenylketonuria (PKU) is a human hereditary disease resulting from the inability of the body to process the chemical phenylalanine, which is contained in the protein we eat. PKU is manifest in early infancy and, if it remains untreated, generally leads to cognitive impairment. PKU is caused by a recessive allele with simple Mendelian inheritance. A couple intends to have children but consults a genetic counselor because the man has a sister with PKU and the woman has a brother with PKU. There are no other known cases in their families. They ask the genetic counselor to determine the probability that their first child will have PKU. What is this probability?arrow_forwardAs a genetic counselor, you inform Susan and John that a blood test for cystic fibrosis is available. would you recommend generic testing for Susan and John?arrow_forwardPlease find an Image/Graphic to represent sickle cell disease: Use at least two different images to help the audience understand the cause and/or inheritance pattern of the disorder you chose. Include a brief 1-2 sentence caption below each image that gives a description of the image and explains its relevance to your chosen disorder. The two images should NOT convey the same exact information. Ideas of images to use include: karyotypes, pedigrees, DNA sequences, etc. Please note: the images should be specific to your chosen disorder. The 2 required images must be related to cause and/or inheritance pattern. Images of an individual with the disorder will not count toward your 2 required images as they do not contribute to the audience's understanding of cause and/or inheritance pattern.arrow_forward
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- Figure 1-15 shows the family tree, or pedigree, for LouiseBenge (Individual VI-1) who suffers from the diseaseACDC because she has two mutant copies of the CD73gene. She has four siblings (VI-2, VI-3, VI-4, and VI-5)who have this disease for the same reason. Do all of the10 children of Louise and her siblings have the samenumber of mutant copies of the CD73 gene, or mightthis number be different for some of the 10 children?arrow_forwardHow much of an impact do environmental factors (such as changes in lifestyle) have on Progeria disease? In regard to testing for Progeria disease why would or wouldn't you want to know if you or your children had or were likely to have the genes associated with this disease?arrow_forwardWhat cause of the genetic disease site your sources provide links to the websites to use?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning