Review Question - QID 109828

A 3-year-old boy is brought in by his parents for placement of a tracheostomy tube in order to allow for better ventilator support of his breathing. At birth, he was flaccid with a poor sucking reflex. Since then, his weakness has progressively worsened such that he is unable to sit, eat, or breathe independently. Family history reveals that his grandfather was affected by a degenerative disorder at age 50, and his father had the same degenerative disorder at age 30. Examination is significant for tongue fasciculations and absent deep tendon reflexes. Which of the following forms of inheritance is associated with the most likely cause of this patient's disorder?