week 3: hemoglobinopathies hemoglobinopathies hemoglobinopathies thalassemia genetics thalassemia...

Week 3: Hemoglobinopathies

HemoglobinopathiesHemoglobinopathies Thalassemia geneticsThalassemia genetics Hb synthesisHb synthesis Hb A, A2, FHb A, A2, F Hb ELPHb ELP Hb Constant-SpringHb Constant-Spring Hb Bart’sHb Bart’s Hb HHb H

Hb LeporeHb Lepore Hb EHb E Hb SHb S Hb CHb C Hb SC diseaseHb SC disease HPFHHPFH

Hemoglobinopathies

Decrease, lack of, or abnormal globinDecrease, lack of, or abnormal globin May be severe hemolytic anemiaMay be severe hemolytic anemia Abnormal Hb with low functionalityAbnormal Hb with low functionality Mutation may be deletion, substitution, Mutation may be deletion, substitution,

elongationelongation Hb electrophoresis may be helpfulHb electrophoresis may be helpful

Hemoglobin

HemeHeme Porphyrin ring and FePorphyrin ring and Fe

GlobinsGlobins Alpha family on chromosome 16Alpha family on chromosome 16

]--//--[]--//--[ Beta family on chromosome 11Beta family on chromosome 11

]--//--[]--//--[]--[]--[[[

Thalassemia 1925: Described by Dr. Thomas Cooley and Dr. Pearl Lee of 1925: Described by Dr. Thomas Cooley and Dr. Pearl Lee of

DetroitDetroit 1920’s: Osmotic fragility test1920’s: Osmotic fragility test 1932: Dr. George Whipple of Rochester coined the name 1932: Dr. George Whipple of Rochester coined the name

“thalassa anemia” from Greek story about Xenophon’s army “thalassa anemia” from Greek story about Xenophon’s army returning from Persiareturning from Persia

1930’s: Familial pattern recognized1930’s: Familial pattern recognized 1950’s: Alkali denaturation test for Hb F, Hb ELP1950’s: Alkali denaturation test for Hb F, Hb ELP 1956: Coulter model A1956: Coulter model A 1960’s: RBC indices1960’s: RBC indices 1980’s: Histogram, DNA analysis, PCR1980’s: Histogram, DNA analysis, PCR

Signs and Symptoms

HemolyticHemolytic Bone changes (hair on end)Bone changes (hair on end) Ethnicity: Mediterranean, Africa, Southeast Ethnicity: Mediterranean, Africa, Southeast

AsiaAsia Hypo-Micro, PoikilocytosisHypo-Micro, Poikilocytosis NRBC’s, reticulocytosis, basophilic NRBC’s, reticulocytosis, basophilic

stipplingstippling Siderocytes (with repeated transfusions)Siderocytes (with repeated transfusions)

Thalassemia Blood Smears

X-ray of scullin Thalassemia:

“Hair-on-end”

Perl’s iron stain (Prussian blue)

with potassium ferrocyanide

Siderocyte

Sideroblasts

Thalassemia

Deletion of one or more alpha genes from Deletion of one or more alpha genes from chromosome 16chromosome 16

--//: silent career with little signs: silent career with little signs --/--/: cis double deletion more common in SEA: cis double deletion more common in SEA --/-/-: trans double deletion: trans double deletion --/---/-: Hb H disease: Hb H disease --/--: Hb Bart’s hydrops fetalis--/--: Hb Bart’s hydrops fetalis Hb Constant-Spring: elongation (discovered in Hb Constant-Spring: elongation (discovered in

Kingston, Jamaica; 2% of Thai have it)Kingston, Jamaica; 2% of Thai have it)

Thalassemia Lab Changes

High RBCHigh RBC Low H&H and indicesLow H&H and indices High RDWHigh RDW May need to rule out IDAMay need to rule out IDA Hb ELP not useful except in Hb HHb ELP not useful except in Hb H BCB prep for Hb HBCB prep for Hb H

Hb H Prep withBrilliant cresyl blue

thalassemiaHydrops fetalis

Peripheral blood smear: Hb H disease

Thalassemia

Usually point mutation in the control regionUsually point mutation in the control region ++ has minimal production has minimal production oo has no production has no production ++//++ or or oo//oo is is thal major or Cooley’s anemia thal major or Cooley’s anemia Often not apparent at birth until Often not apparent at birth until chain takes over chain takes over

chain production chain production High Hb A2, Hb FHigh Hb A2, Hb F Related: Hb Lepore (Related: Hb Lepore ( fusion), HPFH fusion), HPFH

Hb F preparation with Kleihauer-Betke

Fetal Hb resists acid elution

Hb S

Sickling HbSickling Hb AutosomalAutosomal Sickle crisis in low oxygen conditionSickle crisis in low oxygen condition 6 glutamate to valine substitution6 glutamate to valine substitution Prevalent in Eastern AfricaPrevalent in Eastern Africa Solubility testSolubility test Sickling test (meta-bisulfite)Sickling test (meta-bisulfite)

Other Hemoglobinopathies

Hb C (Hb C (6 Glu-Lys) in Western Africa6 Glu-Lys) in Western Africa Cigar-like crystalsCigar-like crystals Billiard ball cellsBilliard ball cells Folded cellsFolded cells

Hb SC diseaseHb SC disease Washington monument cellsWashington monument cells Mitten shapeMitten shape

Hb E (Hb E (26 Glu-Lys) in SEA26 Glu-Lys) in SEA Moves with Hb A2 in Hb ELP and A2 column (ie, Moves with Hb A2 in Hb ELP and A2 column (ie,

false elevated Hb A2)false elevated Hb A2)

Hb SC diseaseHb C disease

Unusual Hemoglobins in the World