Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Physiology 51 Hemoglobinopathies PPT-Powerpoint Presentations and lecture notes
Hemoglobinopathies
Learning Objectives
Hemoglobinopathies (Abnormal Hb variants)
Different Hemoglobin combinations-Nr and Abn
Sickle Cell Trait (
6
21 1 glu-val)
?Sickle cell trait is the heterozygous form of the disease
?Represents a combination of HbA and HbS.
?Individuals with HbS trait are usually asymptomatic or have
mild anemia.
Pathophysiology of Sickle Cell Disease
HbC (2C2) -? Modification - Glutamic acid to lysine at 6
HbD (2d2) -?Modification - Glutamic acid to glutamine at 121
HbE (2e2) -?Modification - Glutamic acid to lysine at 26
Hb Abnormal variants- Quantitative Abnormality
Decreased or absent synthesis of a particular globin chain (structurally normal)
i.e. Thalassemias
Thalassemia
? Common in population of African descent, Southeast Asian, Italians,
Middle Eastern
? Two types-
- thalassemia (Reduced production of - globin chains-HbH or Hb Bart's)
- thalassemia (Reduced production of - globin chains-Cooley's Anemia)
-THALASSEMIA
-THALASSEMIA Trait (Minor): - / , - / -
-THALASSEMIA
-THALASSEMIA Major (4, HbH disease): - - / - ,
Hemoglobin Barts (4 , y-globin tetramer, lethal):
With four-gene deletion: - -/- -
-THALASSEMIA
? One or both -globin genes have mutations that cause partial ( +) or total loss ( O) of
- chain production.
?Decreased synthesis of -globin chains disturbs the balance between the two chains
and -chains precipitate - producing membrane damage and early destruction.
Normal Hb combinations/compounds
Oxyhemoglobin
? Hb reacts with four molecules of O2 to form Hb4O8.
Hb4 + O2 Hb4O2 , Hb4O2 + O2 Hb4O4, Hb4O4 + O2 Hb4O6, Hb4O6 + O2 Hb4O8
https://youtu.be/eor6EK_JP40
Carbaminohemoglobin
Carbaminohemoglobin is a compound of hemoglobin with CO2 (carbon dioxide), and is one
of the forms in which carbon dioxide is transported in the blood at tissue level.
10% of carbon dioxide is carried in blood this way, bound to the globin protein.
Abnormal Hb compound-Methemoglobinemia
?When Fe++ is oxidized to Fe ++ + form in Hemoglobin, this is called as Methemoglobin.
? The affinity of oxygen is impaired in ferric form of iron and binding of oxygen to methemoglobin
results in an increased affinity for oxygen in the remaining heme sites that are in ferrous state within
the same tetrameric hemoglobin unit.
Methemoglobinemia
Sign and Symptoms by Methemoglobin formation % :
?Less than 10% metHb - No symptoms
? 10-20% metHb ?
? >50% metHb -
Treatment
Carboxy-hemoglobin
Carbon monoxide is a colourless, odourless, and tasteless gas that is lighter than air and can be fatal to life.
It has a greater affinity for hemoglobin ( 200 times) than oxygen does. It displaces oxygen and quickly bind
to Hb
SOURCES
Carboxy-hemoglobin
CLINICAL SIGNS
The signs of carbon monoxide poisoning vary with concentration and length of exposure.
TREATMENT
Glycated hemoglobin
A very minute amount of hemoglobin A is continuously and
slowly binds with glucose irreversibly and Non enzymatically with
each chain. This is known as `Glycated Hemoglobin' or HbA1c.
A higher glucose concentration results in more HbA1c.
The normal reference range is approximately 4?5.9%
Self Asessment
Sickle cell trait is the ...............................of the disease, which has mild anemia.
Decreased or absent synthesis of a particular globin chain that is structurally ...............
Thalassemis major has severe anemia, the type is ...........................................................due to
enhanced hemolysis
Hemoglobin Barts has a ....................................and cannot release oxygen to tissues.
-thalassemia major is also called .................. and Microcytic hypochromic anemia
Thank you
This post was last modified on 08 April 2022