Thalassemia: Etiology and Pathology (Pediatric Nursing)

00:01 Now let's talk about thalassemia.

00:03 Thalassemia is an autosomal recessive blood disorder that reduces the production of hemoglobin.

00:09 Patients with thalassemia do not make enough hemoglobin which is the iron-containing protein in red blood cells that carries oxygen to the cells throughout the body.

00:17 When there isn't enough hemoglobin, the body cells don't function properly and the red blood cells die off quicker leaving fewer healthy red blood cells in circulation.

00:26 There two ways to classify thalassemia, this is based either on the alpha or beta type of hemoglobin affected and it can also range in severity and this is either the trait of minor, intermedia or major.

00:39 Symptoms usually appear in the first two years of life and a life-threatening anemia can develop.

00:45 This is a common blood disorder worldwide, thousands of them fence with beta thalassemia are born each year.

00:51 Beta-thalassemia occurs more frequently in patients from the Mediterranean countries, North Africa, the Middle East, India, Central Asia and Southeast Asia Here you can see the distribution of thalassemia and sickle cell anemia and the overlap between them.

01:07 These are both familial disorders passed genetically so it makes sense that we see concentrations of these disorders in certain regions as a mutated genes continue to be passed down through the generations.

01:18 Thalassemia major and thalassemia intermedia are inherited in an autosomal recessive pattern which means both copies of the HBB gene and each cell must have the mutation to display the disease.

01:30 The HBB gene provides instructions for making the protein called beta-globin which is a subunit of hemoglobin The parents of an individual with an autosomal recessive condition can each carry one copy of the mutated gene but they typically don't show any signs and symptoms of the condition, meaning they are carriers.

01:48 In regard to thalassemia, even though it's a recessive disorder, sometimes patients with only one HBB gene and each so can develop a mild anemia.

01:57 And these mildly affected patients are said to have thalassemia minor.

02:02 Here we see two parents who are carriers for the thalassemia gene meaning they have one defective gene and one normal gene.

02:09 They are largely unaffected but they can have a mild anemia.

02:13 With each pregnancy, you can see that their offspring have a 25% chance of developing thalassemia by receiving both mutated genes.

02:21 A 50% chance of being a carrier and being asymptomatic or maybe having a mild anemia, and a 25% chance of not having any mutated genes at all and these patients will have normal hemoglobin.

02:33 Remember the odds reset with each pregnancy.

02:37 People with only one HBB gene can develop a mild anemia.

02:41 This is important to remember, this thalassemia minor and a child can receive a copy of these mutated genes from both parents and then they would have thalassemia major or intermedia.

02:51 Now let's talk about the pathology of thalassemia by comparing normal and abnormal hemoglobin.

02:57 Here is a patient with normal hemoglobin.

02:59 There are no mutated genes to disrupt the hemoglobin so there is a normal amount and it functions normally.

03:05 These patients do not have thalassemia and they are not carriers.

03:09 In the centre you can see a single mutation.

03:11 This patient will be a carrier of beta thalassemia trait also known as thalassemia minor and again they're gonna have hemoglobin but it's not going to have enough and these patients might have a slight anemia.

03:23 On the right, you'll see what happens when a patient has two of the mutated genes and this causes a severe microcytic hypochromic anemia.

03:31 This patient is blood transfusion-dependent and if left untreated they may develop splenomegaly and bone deformities.

03:38 This can progress to death before the age of 20.

03:41 So remember patients with thalassemia lack functional hemoglobin.

03:45 The red blood cells do not develop normally.

03:48 There is a shortage of mature red blood cells and these patients will develop a microcytic hypochromic anemia.