A comprehensive presentation on fetal hemoglobin & Rh incompatibility for undergraduate medical, dental, biotechnology & pharmacology students for self-learning .Presentation has physical & chemical properties of fetal hemoglobin along with its function. Binding affinity for O₂ of HbF and oxygen dissociation curve for HbF elucidated with suitable diagrams. Molecular constitution of Embryonic Hb ( Grover I &Grover II )with electrophoretic patterns are presented here . Importance of Kleihauer staining for detection of fetal cells is described briefly. Diagrammatic representation of Rh- incompatibility is done for complete understanding of the concept. Signs & symptoms Kernicterus are presented diagrammatically. Direct and indirect Coomb’s Test for Rh- incompatibility for diagnosis of Erythroblastosis Fetalis is illustrated. Biochemical aspects of Hemolytic Disease of Newborn (HDN) and Physiological /Neonatal Jaundice are presented. Comparison of Causes & biochemical findings for Hemolytic Jaundice along hepatic and obstructive jaundice is done in this presentation. Molecular mechanism involved in biosynthesis of Hb Bart and Hb H along with their electrophoretic patterns for their detection are illustrated. Hereditary persistent fetal Hb( HPFH ) & Point mutations causing HPFH are described in lucid manner. Google images are used for intense impact of the subject.

2. Fetal hemoglobin ( Hb F )
Hb 2 Alpha (α )chains & 2 Gamma(γ ) or Delta (δ ) chains ( delta chain 146
amino acids , 39amino acids differ from beta chain –embryonic hemoglobin)
Physical chemical properties of Hb F :
1. Increased solubility of Deoxy HbF
2. slower electrophoretic mobility
3. Increased resistance of Hb F to alkali denaturation
4. Decreased interaction with 2,3 BPG
5. Hereditary persistence of HbF ( HPF ) increased HbF without Thalassemia,
no DELTA  BETA gene switching
6. Kleihauer staining for Hb F detection

3. Fetal hemoglobin ( HbF )
• HbF has two γ globin chains carrying less positively charged amino acids.
• Therefore HbF exhibits weak binding affinity towards 2,3 BPG ( negatively
charged ).
• HbF has higher affinity for O₂ compared to adult Hb.
• Binding affinity for O₂ of HbF > HbA (This property of HbF helps to transfer
of O₂ from maternal blood to fetus as HbFO ₂)
• Delivery of O₂ to fetus is important function of fetal hemoglobin .

6. Embryonic Hb - 3-8 weeks
Grover I -zeta ₂ Epsilon ₂ (ζ₂ ε₂ )
Grover II -Alpha ₂ zeta ₂ ( α₂ ε₂ )

7. Kleihauer staining for detection of fetal cells

12. Electrophoretic pattern of fetal hemoglobin

13. Rh- incompatibility

14. Rh- incompatibility
• This condition results from incompatibility between maternal & fetal blood
group. Antigen D existing on membrane of fetal RBC (Rh positive fetus)
induces synthesis of antibodies (anti –D ) in Rh negative mother . In Rh
incompatibility ,the first child often escapes . But in second pregnancy , Rh
antibodies will pass from mother to the fetus. Rh antibodies start destroying
fetal red cells even before birth.
• Sometimes ,the child is born with severe hemolytic disease referred to as
Erythroblastosis Fetalis .
• When bilirubin levels are more than 20 mg/dl ,the capacity of albumin to bind
to bilirubin is exceeded.
• Free bilirubin passes through blood brain barrier and enters the brain.
(Kerniecterus)
• Bilirubin gets deposited in brain leading to mental retardation,fits ,toxic
encephalitis & spasticity.

15. Rh- incompatibility
• If the newborn develops hemolytic disease ( HDN ),the child may be
given exchange transfusion along with phototherapy and
barbiturates ( induce bilirubin metabolizing enzymes in liver).
• Phototherapy with blue light ( 440nm wavelength ) isomerize
insoluble bilirubin to more soluble non toxic isomer ( Lumirubin ).
These can be easily excreted through urine without conjugation.( in
contrast to bilirubin which cannot be excreted without conjugation )

19. This condition results from incompatibility between maternal & fetal blood group. Antigen
D existing on membrane of fetal RBC(Rh positive fetus) induce synthesis of antibodies (anti
–D ) in Rh negative mother .In Rh incompatibility ,the first child often escapes .
But in second pregnancy , Rh antibodies will pass from mother to the fetus. Rh antibodies
start destroying fetal red cells even before birth.
Rh- incompatibility:1

20. In Rh positive fetus:
RBC carry Antigen D on their membrane.
Rh- incompatibility:1a

21. In Rh negative mother :
RBC don’t carry Antigen D on their membrane.
Rh- incompatibility:1b

22. Rh- incompatibility:2

23. Rh- incompatibility:3
Fetal RBC carrying Antigen D
enter the mother circulation
through placenta .

24. Rh- incompatibility:4
In Rh incompatibility : Antigens D on membrane of fetal RBC(Rh positive ) induce synthesis
of antibodies ( anti –D ) in Rh negative mother .

25. Rh- incompatibility:5
In Rh incompatibility Rh antibodies pass from mother to the fetus through placenta.

26. Rh- incompatibility :6
In Rh incompatibility, Rh
antibodies start destroying
fetal red cells even before
birth.

27. Rh- incompatibility:7
In Rh incompatibility, Rh antibodies start destroying fetal red cells even before birth.

28. Rh- incompatibility:8: Erythroblastosis Fetalis

33. Hemolytic Disease of Newborn (HDN )
Rh antibodies will pass from mother to the fetus. Rh antibodies start destroying
fetal red cells even before birth.

34. Hemolytic Disease of Newborn (HDN)  unconjugated Hyperbilirubinemia
Incompatibility between maternal & fetal blood groups
Anti antibodies ABO(IgM type cannot be transferred to placenta)
Rh incompatibility
Fetus mother
Rh ( +ve ) Rh ( -ve )
RBC RBC elicit immune response Anti-D ( IgG )
Destruction Anti-D ( IgG )
Of fetal
RBC ← Placenta
Second pregnancy ( before birth of fetus –destruction of fetal RBC )  child is born with severe hemolytic disease 
Erythroblastosis fetalis

35. Erythroblastosis Fetalis
• Serum Bilirubin  > 20 mg/dl  no more bound to Albumin
• Bilirubin Brain (Kernicterus-deposition of bilirubin in brain )
• Basal ganglia  mental retardation
• ↓ ATPase mitochondria  fits ,spasticity ,toxic encephalitis
• Treatment : (1) phototherapy before age < 1 year 
isomerization ZZ  ZE
(2 ) Blood transfusion

36. • Hemolytic Jaundice
• Causes –
Rh- incompatibility
Hemolysis due to Malaria
Mismatched blood
transfusion,
sickle cell anemia,
• Liver fails to conjugate
excess of Bilirubin
• Therefore
↑unconjugated bilirubin
↑Urobilinogen
↑ stercobilinogen
(brown color stool )
• SGPT / ALP -Normal
• Absence of bilirubin in
Urine
• Hepatic Jaundice
• Causes –dysfunction of
Liver Hepatitis
al infection
poisons/toxins
cirrhosis/CCF
• ↑unconjugated
bilirubin ↑conjugated
bilirubin
↑Urobilinogen
↑ stercobilinogen
(brown color stool )
↑SGPT / ALP
• Obstructive Jaundice
• Gall stone
stool contains fat
unavailability of bile
salts
• ↑conjugated bilirubin
↑Urobilinogen
↓ stercobilinogen
(pale color stool )
↑SGPT / ALP

39. Physiological /Neonatal Jaundice
• Not a truly genetic defect
• Causes : increased hemolysis of RBC with HbF and immature liver
enzyme system for conjugation of bilirubin
• The activity of the enzyme UDP- glucuronyl transferase is low in the
new born.
• The enzyme deficiency is more serious with increasing degree of
prematurity.

43. Fetal hemoglobin ( Hb F )
• Normal Hb F – (2 α 2 γ )
• If α globin not synthesized then synthesis γ & β chain continues 
Tetramers (γ ₄ )—Hb Bart
• β ₄ Tetramers (β ₄ )—Hb H
• HbH lack Heme –Heme interaction

44. Hb H & Hb Bart
Hb lack Heme –Heme interaction
Oxygen dissociation curve -Hyperbolic
No delivery of sufficient oxygen to tissue
Fetal death

46. Hereditary persistent fetal Hb( HPFH )
1. Increase in HbF
2. no clinical symptoms
3. Failure to switch over γ gene to β gene