Common & easy
In the common form, the gut absorbs iron
too well -- something of a plus, but too much iron will ruin the liver, pancreas
, adrenals, heart
drive, and joints (base of thumb especially) and turn you gray.
Easy to test for by labs, and easy to treat by draining a pint or two of blood every week. Maybe one person in 200 has the genes to get it, and some still get missed.