Hemoglobin Opa Thy

7/28/2019 Hemoglobin Opa Thy

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Hemoglobinopathy

Prof. Dr. M Nizam Isa


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Definition

Hemoglobinopathy:A genetic defect that results inabnormal structure of one of the globin chains of thehemoglobin molecule.

Thalassemia:A genetic defect that results in production ofan abnormally low quantity of a given hemoglobin chain orchains.


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Hemoglobinopathy

The genetic defect may be due to

substitution of one amino acid for another (as with the very

common Hb S and Hb C and the great majority of the other

abnormal hemoglobins),

deletion of a portion of the amino acid sequence (Hb Gun Hill),abnormal hybridization between two chains (Hb Lepore), or

abnormal elongation of the globin chain (Hb Constant Spring).

The abnormal chain that results may be the chain (Hb

GPhiladelphia), chain (Hb S, Hb C), chain (Hb F Texas), or

chain (Hb A2Flatbush).


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Hemoglobin (Hb or Hgb) is found in all red blood cells. A hemoglobin they contain

molecule is made up ofheme, an iron-containing complex, and globin, protein chains

that surround the heme complex. The types of protein chains found in the

hemoglobin molecule affect its structure and function. Different types of hemoglobin

are classified according to the type of protein chains.

Normal Hemoglobin Structure


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Hemoglobinopathy Common variants

Hgb A2 (alpha2-delta2)

Hgb F (alpha2-gamma2)

Hgb M

Hgb S

Hgb C

Hgb E Hgb D-Punjab

Hgb O-Arab

Hgb G-Philadelphia

Hgb Hasharon

Hgb Korle-Bu Hgb Lepore


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Thalassemia

The defect may affect the , , , , or epsilon chain, or mayaffect some combination of the chain in the same patient (butnever the and chain together).

The result is an imbalance in production of globin chains and theproduction of an inadequate number of red cells.

The cells which are produced are hypochromic/microcytic andcontain a surfeit of the unaffected chains which cannot

stoichiometrically "mate" with the inadequate supply ofthalassemic chains.

These "bachelor" chains can produce adverse effects on the redcell and lead to destruction of the red cell in the marrow(ineffective erythropoiesis) and in the circulation (hemolysis).

Some hemoglobinopathies may also be thalassemias, in that a

structurally abnormal hemoglobin (hemoglobinopathy) may alsobe underproduced (thalassemia).

Some, but not all, hemoglobinopathies and thalassemias arehemolytic anemias.


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Hemoglobin Structure

,


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Abnormal Globin Structure

Increased O2 affinity The hemoglobin eagerly scarfs up the O2 from the alveoli but then

only stingily gives it up to the peripheral tissues.

Hb Chesapeake and Hb JCapetown Decreased O2 affinity

These hemoglobins are reluctant to pick up O2 from the lung.

Hb Seattle, Hb Vancouver, and Hb Mobile.

Methemoglobinemia

special class of low O2 affinity hemoglobin variants

affected patients have cyanosis, since the methemoglobin is

useless in O2 binding

Hb MSaskatoon and Hb MKankakee


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Unstable hemoglobin (Heinz body anemia)

hemoglobin destabilizes, it forms up into erythrocyte

inclusions called Heinz bodies

Hb Gun Hill, Hb Leiden, and Hb Kln

Sickling and crystallization

Hb S and Hb C, the most important of the abnormal

hemoglobins


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Hemoglobin S and sickle cell disease

Hemoglobin C

The gene for Hb C is also prevalent in the African-American

population but with less frequency (2-3%) than that of thesickle cell gene.

An individual may inherit a Hb S gene from one parent and a

Hb C gene from the other. The result of this double whammy

is Hb SC disease.


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Hemoglobin EThis is a very common chain mutation among Southeast

Asians.

Thai, Khmer, Burmese, Malays, Vietnamese, Bengalis and HanChinese and Japanese

Resembling some cases of thalassemia minor

Hemoglobin E should always be considered working up an

unexplained microcytosis in a member of one of the

affected ethnic groups.


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Rbc Morphology

Hb AC
http://bloodjournal.hematologylibrary.org/cgi/content/full/112/5/1581/FU1


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Rbc Morphology

Hemoglobin H


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Hb Electrophoresis


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RBC Indices


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Automated Hematology Analyser

cost effective and compact.

fully automated comprehensive

non-toxic reagent system.

accurate, reliable measurement of rbc, plt

and hgb.complete wbc 5-part differential.

simple operation via touch-sensitive color

screen.

useful software program for convenient

data management.

user friendly operating system for reliabletesting.

system expandability for greater

performance.

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Hemoglobin Opa Thy