Transcription
Hey everybody, let's talk about thalassemia. As we've reviewed before, we're talking about microcytic anemia. We have discussed iron deficiency anemia, anemia of chronic disease, and now let's talk about thalassemia.
Symptoms of anemia? Tired and pale, pale and tired. So, depending on the MCV, or the mean corpuscular volume, we can classify anemia into microcytic, normocytic, or macrocytic. Usually, thalassemia will be microcytic; MCV is less than 80. But what does the word even mean? Thalassemia, fellows, means "sea" in Greek; "-emia" or "-hemia" means blood. So it's a blood disorder due to a problem related to the Mediterranean Sea—Italy, for example, North Africa, etc. Genetically speaking, it's an autosomal recessive condition. Mommy and daddy are carriers; 25% of the offspring will be affected with the condition (β-thalassemia); the other 50% will be carriers; and 25% will be completely normal. Autosomal recessive disease, microcytic anemia.
To understand them, we need to understand that hemoglobin consists of heme and globin. Heme consists of iron and protoporphyrin. So, both iron deficiency anemia and anemia of chronic disease—the problem is in the iron. I am deficient in iron; I cannot utilize the iron. In aplastic anemia, the problem is in the protoporphyrin pathway. Thalassemia—today's topic—the problem is in the globin. "-in" means protein. In the previous video, we have talked about the hemoglobin's four subunits: two alpha and two beta proteins. Those are the protein subunits, the alpha and beta, plus heme components consisting of protoporphyrin and iron. So the hemoglobin has four globin subunits—two alpha and two beta—and heme groups also followed them. Okay? Remember, in adults, hemoglobin A should be 95%, okay, at least; it's usually more than 97.5%. Hemoglobin A2 should be less than 2.5%, generally speaking, and hemoglobin F, it's fetal, should be very minimal.
So, if the defect is in the alpha chain or alpha subunit, we'll call it alpha-thalassemia. If that defect is in the beta subunit, we'll call it beta-thalassemia. Okay? Those are the two different types: either alpha-thalassemia or beta-thalassemia. So if there is a defect in one of them, something called heme precipitates will be formed. Okay? They will precipitate in the RBCs because they are water-insoluble, and then they will lead to ineffective erythropoiesis. And if globin chains are decreased, hemoglobin will be decreased; hence anemia, because anemia is low hemoglobin and hematocrit.
The next video, we'll discuss what's the difference between alpha-thalassemia and beta-thalassemia. Stay tuned and please subscribe. I'll see you in the next video. Peace.