Yes, there is such a hereditary disease as porphyria, in which the non-protein part of hemoglobin hem is not formed, as a result of which intermediate products of its synthesis - porphyrinogens - accumulate. In the light, they turn into porphyrins, which, when interacting with atmospheric oxygen, form active radicals that damage skin cells. The skin begins to acquire a brown tint, becomes thinner and bursts from exposure to sunlight with the formation of ulcers. The gums are also affected, there is terrible stomatitis and gingivitis, from which the roots of the teeth are exposed and bleed (looks like a vampire). And also the nervous system suffers greatly: there may be hallucinations, aggression and an insane state. From the sun, their skin damage is only aggravated. In northern Europe, this disease is most common and is born in 10-12 people per 100,000 and in our time with this condition. It is treated with a bone marrow transplant.
Lack of hemoglobin? This is iron deficiency anemia. The disease, described along and across, and really something, but the desire to gnaw other people's veins and drink someone else's blood with it is definitely not observed)) Well, so why should you drink blood to increase iron in your blood; if we talk about a good source of iron with nutrition, it is any meat.
Not necessarily human))) Beef / pork / dog meat / lamb / chicken - very even))