Same with my sister. She has 5 kids that run the whole range.
There are several versions of one gene that can create all sorts of problems ~ including iron deficiency anemia, or pernicious anemia.
Gene A simply gives you anomalous heme ~ with the result that you end up dumping half your iron intake down the toilet as urine. You will invariably have a Vitamin B-12 deficiency unless you consume enormous quantities of meat or sublingual Vitamin B 12 pills (available at Wal-Mart $5.00 a bottle). Remember crazy old aunt Betty who got those shots once a month? They don't do the shots anymore.
Gene B is a bit more serious and you will have the same iron loss, and skin problems, and possibly some psychological problems. This one is fortunately far less common.
Then there's Gene C and it has a sort of psychotic behavior. Only 500 individuals with this gene have been found in Scandinavia. SImple injections of carbohydrates (sugar) will alleviate most psychotic episodes ~ assuming you can catch them as they run off across the tundra.
However, when it comes to shedding iron in the urine, these guys shed it in photoreactive form and it can turn PURPLE or VIOLET.