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Olivia S. was born with a rare recessive disorder called tyrosinemia. The next day, Olivia M. was born in a neighboring state with the same disorder. Tyrosinemia is caused by the lack of an enzyme win the degradation pathway of the amino acid tyrosine. Accumulation of metabolic intermediates causes progressive liver dysfunction and kidney problems. One-year-old Olivia S. is healthy and has no symptoms of the disorder. At the same age, Olivia M. developed liver failure. Olivia S. was born in a state where newborns are tested for tyrosinemia, but Olivia M. was born in a state where newborns are not tested for this disorder. A week after diagnosis, Olivia S. was placed on a low-tyrosine diet and prescribed a drug to block the accumulation of metabolic intermediates. Olivia M. was not diagnosed until she was in liver failure; she then was placed on a low-tyrosine diet, was prescribed medication, and underwent a liver transplant. She faces of lifetime of antirejection drug therapy and may require a kidney transplant. In the United States, newborn screening programs are developed independently by each state and are often based on a cost-benefit analysis to decide which diseases are included in testing. In the United States, tyrosinemia occurs in ony 1/100,000 live births, and in this case, two states made different decisions about newborn testing for this disorder. 1. In a region of Quebec, Canada, 1 in 22 people are heterozygous for the mutant tyrosinemia allele. Using the frequency of heterozygotes, calculate the frequency of recessive homozygotes in this population. What might explain the difference between the frequency of tyrosinemia in the U.S. population and in this particular Canadian population? 2. Critics argue that a uniform panel of disorder4s should be used by all states for newborn testing. Aside from cost-benefit ratios, what would you regard as ethical guidelines for use in deciding which disorders to include or exclude in a newborn testing program? 3. Others argue that the current testing program should be replaced by whole genome sequencing for all newborns. What do you see as the ethical pros and cons of this position?