A 3-year-old boy is brought to the dermatology clinic by his parents due to blistering skin lesions and scarring on sun-exposed areas. The parents report that these symptoms have been present since infancy and worsen with sun exposure. The child also has hypertrichosis, dark reddish-brown discoloration of the teeth, and a history of pink-stained diapers. Physical examination reveals vesicles, bullae, erosions, crusting, and hyperpigmented scars on the face and hands. Laboratory studies show hemolytic anemia and hepatosplenomegaly. Which of the following is the most likely diagnosis?
