Human Heredity 9th Edition by Michael Cummings

Exercise 2

Tina is 12 years old. Although symptomatic since infancy, she was not diagnosed with acid maltase deficiency (AMD; OMIM 232300) until she was 10 years old. The progression of her disease has been slow and insidious. She has difficulty walking and breathing because of severe muscle weakness. She relies on a respirator to assist her breathing. Tina has severe scoliosis (curvature of the spine), which further restricts her breathing and causes even greater difficulty in walking. She is extremely tired and experiences constant muscle pain. Although she is very bright and thinks like a normal teenager, her body won't let her function like one. She can no longer attend school. The future is bleak for Tina and other children like her. Death from the childhood form of AMD is frequently due to complications from respiratory infections, which are a constant threat. Life expectancy in this form of AMD is only to the second or third decade of life.
AMD, also called glycogen storage disease type II (or Pompe disease), is an autosomal recessive condition. Heterozygous parents have a 25% chance during each pregnancy that the child will have two abnormal genes and be affected.
Normally, glycogen is synthesized from sugars and is stored in the muscle cells for future use. The acid maltase enzyme breaks down the glycogen in the muscle cells when sugar is required as an energy source. Someone with AMD lacks this enzyme, and glycogen gradually builds up in the muscles, leading to progressive muscle weakness and degeneration.
There is no cure for AMD. Enzyme replacement is being used to successfully treat this disorder and offers new hope for children like Tina, but such treatments are expensive (often more than $100,000 per year) and must be continued for life.
As enzyme therapies for other disorders are developed, funding these therapies will become prohibitively expensive. Tina is 12 years old, and her life expectancy is 20 to 30 years. Should there be a lifetime limit on how much money should be spent on Tina's treatment?