Patients with the genetic disorder Duchenne muscular dystrophy experience progressive muscle wasting that leads to progressive loss of ambulation, respiratory failure, and ultimately death. Laboratory studies reveal elevated serum levels of the enzyme creatine kinase. It is inherited in an X-linked recessive pattern, with the affected gene being one that encodes for the protein dystrophin. Unfortunately, life expectancy is rarely beyond age 30.
What statement correctly describes this disorder?
1) It is a disorder that leads to progressive muscle wasting and ultimately death.
2) It is inherited in an X-linked recessive pattern.
3) Patients with this disorder have elevated serum levels of the enzyme creatine kinase.
4) Life expectancy for patients with this disorder is rarely beyond age 30.