Altered Developmental Expression of Clotting Factor IX (Hemophilia B Leyden)
Yet another type of hemophilia genetic bleeding disorder, Hemophilia B Leyden (HBL), is also a rare disorder caused by problems with blood clotting factor IX (FIX). Unlike the regular Christmas disease, however, this rare subtype of hemophilia B is distinct as it starts very early in life.
HBL is characterized by deficient FIX levels, which disrupts the DNA activator region. The difference is, with HBL, the promoter region affected by the disrupted activator region still responds to hormones, so by the time the HBL patient reaches puberty, the gene expression and production of FIX reach the low end of the normal range, eclipsing the blood clotting problem.
Unlike the others, this rare form of hemophilia is said to be impermanent as hormones that run rampant during adolescence may trigger an opposite reaction, allowing gene expression. This reaction then triggers the DNA region that otherwise inhibits the production of clotting factor IX, resulting in the body’s low-end to normal range activity levels of FIX. In short, with HBL, adolescence can normalize bleeding, and those afflicted with it are almost normal because they no longer necessarily bleed for a long while.
