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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 daughter’s 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?
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Human Heredity: Principles and Issues (MindTap Course List)
- A couple has had a child born with neurofibromatosis. They come to your genetic counseling office for help. After taking an extensive family history, you determine that there is no history of this disease on either side of the family. The couple wants to have another child and wants to be advised about the risks of that child having neurofibromatosis. What advice do you give them?arrow_forwardAt her first prenatal visit, a woman relates that her maternal aunt has cystic fibrosis, an autosomal recessive illness. Which of the following statements is appropriate for the nurse to make? a. It is unnecessary for you to worry since our aunt is not a direct relation." b. "We can check to see whether or not you are a carrier for cystic fibrosis." c. "You should have an amniocentesis to see whether or not your child has the disease." d. Please ask your mother whether she has ever had any symptoms of cystic fibrosisarrow_forwardA 22-year-old man enters the clinic with a wide-stepping gait, muscle wasting, myotonia, and bilateral cataracts. His father, who is 55, currently suffers from similar symptoms, which began about 5 years ago. His father's sister also exhibits similar symptoms; hers also began in her 50s. The patient's mother exhibits none of these symptoms. What is the inheritance pattern of this patient's most likely disease?arrow_forward
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- Alfred is heterozygous for tongue rolling and has five fingers. Alfreda, his wife, cannot roll her tongue and is heterozygous for polydactyly. Use R/r for tounge rolling, P/p for polydactyly. What is Alfred’s genotype? ____________ What is Alfreda’s genotype? ____________arrow_forwardMr and Mrs Connelly are planning to start a family. However, Mr Connelly is concerned that, as his brother was diagnosed with cystic fibrosis (CF), he may be a CF carrier. Their GP explains how Mr Connelly may carry the faulty CFTR gene using a Punnett square. create a Punnett square to show possible outcomes for their children if Mr Connelly is a CFTR carrier but his wife is not and explain the results in detail.arrow_forwardBoth parents love strawberry blonde hair but hate the fact they can touch their noses with their tongues. What are the odds their child will be a strawberry blonde non-nose touching individual?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning