Five Quarts_ A Personal and Natural History of Blood - Bill Hayes [82]
That Leopold survived into his early thirties is medically remarkable. Most bleeders in his day never made it into adolescence. In fact, individuals with severe hemophilia faced a similar mortality rate well into the 1960s. To answer definitively why Prince Leopold lived as long as he did, however, would require something that simply no longer exists: a sample of his blood. With it, a modern hematologist would be able to find exactly what was missing. Without it, a good guess is still possible. But first, some basics are in order.
The simplest way to describe coagulation is to say it’s a complex process in which blood turns from a liquid to a solid. As many as twenty different blood proteins take part in this coordinated effort—what one scientist with a touch of the poet named “the clotting cascade.” Thirteen of these blood proteins are called factors, and a deficiency of any one results in a different clotting or bleeding disorder. To picture the prevalence in the general population, imagine a twenty-thousand-seat sports stadium filled to capacity and split evenly between the sexes. Four hundred attendees, men and women alike, would have the most common bleeding disorder, von Willebrand’s disease, in which a deficiency of the von Willebrand factor keeps platelets from clumping properly at the site of an injury. Just two attendees, men only this time, would have hemophilia A, or classic hemophilia, which is caused by a lack of factor VIII. To find a single gentleman with hemophilia B, two additional stadiums are needed (one in thirty thousand men have this deficiency in factor IX). Now on to a bigger challenge. To find a woman with classic hemophilia, one should probably scrap the whole stadium idea and consider instead the entire population of the United States. One in one hundred million citizens is this rarest of the rare, a female hemophiliac. Its infrequency in women is simply a matter of genetics, the female XX versus the male XY. The recessive gene for hemophilia rides the X chromosome. In a female, if one X is defective, the other can normally compensate. It would take the pairing of two defective X’s for the condition to develop.
In males, the first sign of a serious bleeding disorder often comes when a baby boy is circumcised, a danger that has been recognized since ancient times. In the Babylonian Talmud, the collection of Jewish rabbinical laws written between the third and sixth centuries, it was declared that a newborn son would be excused from circumcision if two brothers had previously died from the procedure. From a modern standpoint, this law calls to mind a common misconception that should be stanched forthwith: that a hemophiliac with, say, a minor wound will never stop bleeding. The lack of factor VIII or IX doesn’t mean your blood won’t ever coagulate; the woodwinds may be absent, so to speak, but the orchestra still plays. Other components of the clotting cascade continue to do their job. The problem is, you clot more slowly and hence bleed longer. How long depends largely upon how much clotting factor is present in your blood. Analyses of blood can calculate the speed of your clotting as well as pinpoint which factor is deficient and in what quantity. A person with mild hemophilia, for instance, will have, at best, only half the clotting activity of a healthy person. By contrast, in severe hemophilia, the amount is less than one one-hundredth of normal. Once these calculations are determined, treatment is fairly straightforward, at least in theory. You simply inject or infuse the missing substance. And of course the earlier in a person’s life that these levels are assessed, the better.
Regarding Leopold, it is possible to piece together details of his condition through his words, for the young man’s personal correspondence lays bare his suffering. A well-understood medical consequence of severe hemophilia