Bombs, concealed weapons, spare change at the beach – metal detectors were designed to help us find all sorts of things, but what if I told you they could also pick up on genetic diseases? While not practical (or medicolegally acceptable), they may provide a clue to the diagnosis of a rare inherited disorder.
The disease I’m speaking of is called hereditary hemochromatosis – the result of a gene mutation that causes a derangement of iron metabolism. Normally, we in the West enjoy a diet that provides between 10-20mg daily, only about 10% of which is absorbed – just enough to offset daily losses. In hemochromatosis, intestinal iron absorption is accelerated and as excess iron accumulates it is deposited in tissues.
The primary organs affected include the liver (causing cirrhosis), the heart (causing a restrictive cardiomyopathy), and the endocrine glands (resulting in an array of effects from hyperglycemia to sexual dysfunction). And because people with hemochromotosis can develop insulin deficiency and skin hyperpigmentation, it has been referred to as “bronze diabetes.”
Though the problem is present at birth, patients often don’t experience any symptoms that lead to a doctor’s visit (and a diagnosis) until their 40s or 50s. During this long asymptomatic period, total body iron stores can reach values in excess of 30-50 grams – more than 10 times the amount normally present in the body, and enough to set off metal detectors at airports (and you think the TSA gives you a hard time now?).
Thankfully, there is an effective treatment that is almost painless, has few side effects, and requires little technical skill – and it’s been around as long as medicine itself has (or longer, depending on who’s counting):
Classic bloodletting has fallen out of favor (or perhaps more accurately, has been debunked), and today we refer to the act as therapeutic phlebotomy (PC terms are so boring). The frequency of phlebotomy depends on the individual’s iron load – typically quite often (e.g. weekly) at the beginning of treatment, then tapered down to once every 30 to 90 days. For acute iron overload (i.e. poisoning) or individuals who can’t tolerate phlebotomy, chelating agents like deferoxamine are available.
So the next time you see that poor guy stripping down to his travel boxers but still setting the detectors off, consider this diagnosis!
Bonus fact: Now the most common hereditary disease in persons of northern European descent, the genetics of hemochromatosis have been traced back to a single Celtic/Viking ancestor (and has even been referred to as the “Celtic Curse”). Perhaps the Vikings had a greater influence than the history books lead us to believe.