A 36-year-old male presents to the clinic with concerns about increasing weak-
ness and fatigue. He reports that his symptoms are present at all times, but at
times of stress, the weakness is much worse. He has had some nausea, vomit-
ing, and nonspecific abdominal pain, resulting in involuntary weight loss. His
skin coloration has changed similar to a tan and is all over his body. On exam,
he is in no distress with normal vitals other than a slightly low blood pressure.
His skin is bronze in color with darkening in elbows and creases of the hand,
although he states that he avoids the sun. The remainder of the exam is normal.
What is the likely diagnosis?
What is the underlying molecular disorder?