12 Thalassemia

Globin

• alpha chain very important: component of all 3 types

• beta thalassemia only affects A

• sample from patient in gel with electrical charge

Thalassemia

• decreased hemoglobin causes thalassemia

Alpha

• top right: normal, 2 alpha on each copy of Ch 16

• alpha: gene deletion

• depending on number missing, severity

• if not lead poisoning, sideroblastic, or iron, suspect thalassemia

• use electrophoresis to determine alpha or beta

Minima

• only risk is pass to offspring

Minor

• cis more risk: parent can pass 2 deleted genes to offspring

• trans: can only pass on one deleted gene

HbH Disease

• excess beta globin but can't combine with alpha globin

• binds O2 but won't release

• cleared by spleen

• can look a lot like iron deficiency, but never see hemolysis (high bilirubin, splenomegaly) in iron deficiency

Bart

• negative coombs test, compared to erythroblastosis fetalis

Beta

• mutation can result in no function or some function

• minor: 1 mutated gene

• major: both genes mutated

• if not lead poisoning, sideroblastic, or iron, suspect thalassemia

• use electrophoresis to determine alpha or beta

• mediterranean thalassemia

• italy/greece.,

Minor

• still makes enough to be asymptomatic

• increased A2 is hallmark of minor

Major

• severe anemia and reduced RBC count

• lots of abnormalities on smear

• extra cell membrane or shrink volume

• decreased volume with low Hb

• bone marrow working so hard to make RBC: abnormal skull/face

• crew cut: skull with fine points sticking out of it

• liver/spleen make RBC with very high EPO

Intermedia

• symptoms of anemia but not severe enough to require transfusion

Misc

• just as likely to be infected as others, but less severe

• thalassemia: genetic disorder, all RBC affected

• only for mild, not major