Thalassemia is a genetic blood disorder characterized by abnormal hemoglobin production, leading to inadequate red blood cell production and anemia. It affects the body’s ability to produce hemoglobin, which is essential for transporting oxygen throughout the body. Thalassemia can range from mild to severe forms, with symptoms including fatigue, weakness, pale skin, and complications like bone deformities and organ damage. There are different types of thalassemia, including alpha and beta thalassemia, each with varying degrees of severity. Treatment may involve blood transfusions, iron chelation therapy, and in severe cases, bone marrow transplant.

1. Thalassemia
Presenter: Dr. Sunil Bhawariya, MBBS, DNB General Medicine
Moderator: Dr. Gopal Bhardwaj

2. Thalassemia:-
It is a quantitative hemoglobinopathy caused by reduced accumulation of
either alpha or beta chains causing a relative excess of the unaffected chain.
The beta globin gene cluster on short arm of chr. 11(11p15.4)
The alpha globin gene cluster is on chr 16(16p13.3)
alpha globin polypeptide contains 141 AA.
beta globins have 146 AA.

3. Name Description Composition
Hb A Adult Hb a2b2
Hb A2 Minor adult Hb a2d2
Hb F Fetal Hb a2g2
Hb Barts Abnormal Hb g4
Hb H Abnormal Hb b4

4. %
total
hemoglobin
gestational age
(weeks)
postnatal age
(weeks)
12 36
24 48
birth
6 30
18
10
20
30
40
50
β
β
δ
α α
ζ,ε
γ
γ
Hemoglobins Throughout Development
Hb F Hb A
fetal life postnatal life
Hb A2
Image courtesy of Charles Quinn

5. Methods of Hemoglobin Identification
• All Hb separation techniques do
not conclusively establish the
identity of a Hb, they only provide
evidence for a particular Hb based
on comparison with migration or
elution characteristics of known
Hbs.
• Hemoglobin Electrophoresis
• At least two methods are needed to
identify a variant Hb.
• Citrate is often used to confirm the
presence of Hb S or Hb C.
• Isoelectric Focusing (IEF)
• Advantages over cellulose acetate:
sharper bands, better separation of
some variants.
• High Performance Liquid
Chromatography (HPLC)
• Advantages over IEF and gel-based
electrophoresis: smaller sample
volume, automation, higher
throughput.

6. Quantitative Hemoglobinopathies - Thalassemia
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

7. Basic Nomenclature of Thalassemia
• Genetic Defect
• α-thalassemia: defect in α globins
• Deletions; absence of α globin genes
• β-thalassemia: defect in β globins
• Single nucleotide changes are the most common β thalassemia mutations, but gene
deletions also occur.
• Point mutations disrupt regulatory elements of gene expression, gene trascription
• Clinical Severity
• Minor / trait: mild anemia, asymptomatic
• Intermedia / NTDT: moderate anemia, signs/symptoms, some transfusions
• Major / TDT: severe anemia, transfusion-dependent
NTDT = non-transfusion-dependent thalassemia
TDT= transfusion-dependent thalassemia

8. Pathophysiology of Thalassemia
Decreased production of a or b globins
Imbalance between a and b globins
Absence of complimentary globin chain causes non-formation of functional Hb tetramers
Ineffective erythropoiesis
Anemia Increased intestinal
iron absorption
Extramedullary
hematopoiesis
Bone marrow
expansion

9. Thalassemia
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

10. Geographical Distribution of Thalassemia
https://commons.wikimedia.org/w/index.php?curid=11568835

11. Thalassemia
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

12. Condition Hgb F Hgb A2
Beta thalassemia trait
Normal or Increased
(1 – 10%)
Increased
(3 – 10%)
Alpha thalassemia trait
Normal
(0 – 2%)
Normal or Decreased
(0 – 2.5%)
Iron deficiency anemia
Normal
(0 – 2%)
Normal or Decreased
(0 – 2.5%)
Normal Hgb F: ≈ 0 – 2%* Normal Hgb A2: ≈ 2 – 3%*
Key Points:
Beta thalassemia trait: diagnosis can be confirmed by electrophoresis.
Alpha thalassemia trait: diagnosis of exclusion (electrophoresis may be normal).
Iron deficiency anemia: mimics a-thalassemia trait, masks b-thalassemia trait.
Treat iron deficiency before performing electrophoresis.
Basics of Electrophoresis
Differentiation of thalassemia trait from mild iron deficiency anemia
*Normal range after 6 months of age. Range varies by technique and lab.

13. Overview of Alpha Thalassemia
Common (Classical) Genotypes
Genotype a genes Name
aa / aa 4 Normal
aa / a– 3 Silent carrier
– – / aa 2
2
Thalassemia trait
a– / a–
– – / a– 1 Hgb H disease
– – / aCSa 1 Hgb H-Constant Spring
– – / – – 0 Hydrops fetalis
minor
intermedia
NTDT
major
TDT
a-thalassemia-2: a –
a-thalassemia-1: – –
Older terms:

15. a-/a-
trans deletions
 aa
  aa
aa aa aaaa
a a
a aa aa
a aa aa
No thalassemia major 25% thalassemia major
--/aa
cis deletions
Risk of Thalassemia Major in Offspring
Depends on Trait Genotype
Image courtesy of Charles Quinn

16. Hb H Disease
Genotypes Classical: – – / a –
Others: – – / aCSa
Neonates Excess g  25–50% Hb Barts (g4)
Microcytosis (MCV <95 fL)
Children and
Adults
Excess b  5-10% Hb H (b4) – fast band on IEF
Moderate to severe anemia (Hb 6–9 g/dL)
Hyphochromia and microcytosis (MCV 55–65 fL)
Hepatosplenomegaly
Hb H inclusions on brilliant cresyl blue (BCB) stain
Significance Great phenotypic variability
Hemochromatosis from increased iron absorption and transfusions
aCS = Hb Constant Spring
Hb H inclusions
(supravital stain)

17. Homozygous alpha thalassemia
Hydrops Fetalis
Genotype – – / – –
Embryo and
Fetus
Nearly 100% Hb Barts and Hb H
Possible embryonic Hb formation (if ζ not deleted)
Non-immune fetal hydrops and demise
Potential
Medical
Support
In utero transfusions
Post-natal chronic transfusions or SCT
SCT = stem cell transplantation

18. Genotype Description
b / b Normal
b / b0
Beta thalassemia trait (minor)
b / b+
b+ / b+
Beta thalassemia intermedia
b+ / b0
bE / b+
bE / b0
b0 / b0 Beta thalassemia major
Overview of Beta Thalassemia
Common (Classical) Genotypes
Production of b-globin:
b+ = decreased
b0 = absent

20. Beta Thalassemia Trait
Genotypes bb+
bb0
Neonates Normal blood counts
g (not b) is the predominant b-like globin
Children and
Adults
Mild to no anemia (Hb 10–12 g/dL)
Hyphochromia and microcytsis (MCV 65–75 fL)
Hb A2 (and sometimes Hb F) increased
Significance Common
Frequently misdiagnosed and treated as iron deficiency anemia
Risk to offspring
TI = thalassemia intermedia
TM = thalassemia major
hypochromia, microcytosis,
target cells, anisopoikilocytosis

21. Beta Thalassemia Intermedia
Genotypes b+b+ b+b0 bE/b+ bEb0
Neonates Normal blood counts
g (not bor bE) is the predominant b-like globin
Children and Adults Mild to moderately severe anemia
Hyphochromia and microcytsis (MCV 50–65 fL)
Hb A2 and F increased
Variable hepatosplenomegaly
Significance Some require intermittent transfusions
Hemochromatosis from increased iron absorption (and transfusions)
TI = thalassemia intermedia
TM = thalassemia major

22. Beta Thalassemia Major
Genotypes b0b0
Neonates Normal blood counts
All Hb F (no Hb A)
Newborn screen: F only pattern
Children and
Adults
Progressively severe anemia during the first year of life
Produce Hb F and A2 only
Severe hypochromic microcytic anemia
Organomegaly and growth failure
Significance Lifelong transfusions or transplantation needed
Hemochromatosis from increased iron absorption and
transfusions

23. Thalassemia
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

24. Therapy for Thalassemia Intermedia or Major
• Cure by stem cell transplantation (HLA-matched sibling donor)
• Chronic transfusions (“hypertransfusion”)
• Common indications: severe/symptomatic anemia, growth failure, problematic
extramedullary hematopoiesis.
• Frequency: every 2-4 weeks (nadir Hb ≈ 9-10 g/dL with suppressed retic count)
• Therapeutic goals:
• Alleviate symptomatic anemia
• Greatly suppress ineffective erythropoiesis
• Prevent bony complications and decrease organomegaly
• Improve growth, development, quality of life
• Chelation therapy for iron overload
• Consider splenectomy for marked hypersplenism (e.g., increased
transfusion requirements, discomfort)—avoid if possible

25. Assessment Ages Frequency Comments
Bone mineral density ≥ 10 Yearly DEXA scan or quantitative CT
Tanner Stage 10 to 20 Yearly Perform yearly starting at age 10 and continuing until
breast or gonadal Tanner stage V or age 20.
Liver Iron Content all Yearly MRI (R2, T2*) or liver biopsy
Cardiac T2* ≥ 10 Yearly To be performed when available for patients with
biochemical evidence of iron overload or age 10 years or
older
Cardiac Studies ≥ 10 Yearly Echocardiography and/or cardiac function by MRI;
indicate the need to assess for pulmonary hypertension
when ordering an echocardiogram
CBC plus differential all Yearly (minimum) If transfused, preceding each transfusion
Blood chemistries all Yearly BUN, creatinine, calcium, magnesium, phosphorus, and
zinc
LFTs all Yearly ALT, AST, total bilirubin, albumin
Ferritin all Yearly (minimum) If transfused, preceding each transfusion
HIV all Yearly Only for transfused participants starting at the first
transfusion
Hepatitis serology all Yearly Only for transfused participants starting at the first
transfusion.
Fasting plasma
ascorbate
all Yearly 12 hour fast
Fasting glucose ≥ 10 Yearly 12 hour fast
Endocrine panel I ≥ 6 Yearly TSH, free T4, parathyroid hormone, 25-hydroxy vitamin
D, and 1,25 dihydroxy vitamin D levels
Endocrine panel II ≥ 10 Yearly Testosterone (males only), FSH and LH (males and
females), and estradiol (females only)
Recommended standard care for thalassemia intermedia and major

26. Transfusional Iron Overload
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

27. iron stores increase
capacity of transferrin exceeded
unbound iron accumulates
iron accumulates in
organs
free radicals and
reactive oxygen species
peroxidation of membrane
lipids and cellular injury
cardiac, endocrine, hepatic and
joint toxicity
Accumulation of Iron: Hemochromatosis
Blood
transfusions
Increased
intestinal
absorption

28. Transfusional Iron Overload
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

29. Organ Accumulation of Iron
• Liver
• Cirrhosis
• Liver Failure
• Hepatocellular Carcinoma
• Heart
• Heart Failure
• Dysrhythmias
• Sudden Death
• Pituitary
• Hypogonadism
• Hypothyroidism
• Growth Failure
• Pancreas
• Diabetes
• Parathyroid glands
• Hypocalcemia
• Skin
• Hyperpigmentation

30. Transfusional Iron Overload
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

31. Determination of Iron Loading
Transferrin Saturation
A high TSAT (≥45 percent in males or ≥40 percent in females;) often occurs with iron overload ; a TSAT below
these levels is good evidence that the patient does not have iron overload, even if the ferritin is elevated.
An elevated TSAT with a normal ferritin suggests that the individual is at risk for, or in the early stages of, iron
overload.

32. Determination of Iron Loading
• Serum Ferritin – Indirect
Measurement
• May not accurately represent a patient’s
risk
• Non-linear with iron load
• Confounded by inflammation and vitamin C
deficiency
• Underestimates iron burden in thalassemia
intermedia and Diamond-Blackfan anemia
• Cannot substitute for more direct
determinations of iron load in susceptible
organs.
• Liver biopsy
• may occasionally be necessary for
histologic determination of fibrosis or
cirrhosis.
• MRI Imaging
• Non-invasive in vivo iron quantification
• Magnetic properties of ferritin and
hemosiderin alter MR signal

33. Transfusional Iron Overload
1. Basic Science and Pathophysiology
2. Epidemiology and Risk Assessment
3. Diagnosis
4. Management and Treatment

34. Treatment Options for Iron Overload
• Chelation Therapy
• Often wait until age > 2 years because of potential growth impairment and
bony changes (especially for deferoxamine).
• Red Cell Exchange
• Red blood cell exchange (RBCx) is a nonsurgical therapy that removes
abnormal red blood cells and replaces them with healthy red blood
cells provided from blood donors.
• Phlebotomy

35. Common Iron Chelators
Oral Chelators
• Deferasirox
• Oral solution (dissolved tablet)
• Once daily
• Main toxicity: GI, hepatic, renal
• Monitoring: Monthly ferritin, LFTs,
BUN/creatinine, urine prot:creat
• Deferiprone
• Tablets
• Three times a day
• Main toxicity: neutropenia
• Monitoring: Baseline and weekly
ANC; monthly ferritin, LFTs
IV/Subcu Chelators
• Deferoxamine
• Hexadentate iron chelator
• SQ or IV infusion (short t1/2)
• 10-12 hrs, 5-7 nights weekly
• Main toxicity: ocular, otic, bony
• Monitoring: : Monthly ferritin, LFTs,
BUN/creatinine, urine prot:creat;
yearly eye exam and audiogram;
consider yearly bone density

36. Other Hemoglobinopathies
• Hemoglobin E
• Hereditary Persistence of Fetal Hemoglobin (HPFH)
• Hemoglobin Constant Spring

37. Hemoglobin E
Very common Hb variant (Southeast Asia)
• b26 glulys [HBB.c.79G>A(p.E27K)]
• Qualitative and quantitative defect (thalassemic hemoglobinopathy)
• Interacts with b-thalassemia determinants
Name Main Hb Present Clinical features (generalization)
Hb E trait A > E Microcytosis, target cells
Hb E disease E
Mild microcytic anemia, target
cells
Hb E / β+ -thalassemia E > A β-thalassemia minor to intermedia
Hb E / β0 -thalassemia E β-thalassemia intermedia to major
Clinical Spectrum of Hb E Disorders
Hb E/β-thalassemia syndromes are managed like other β-thalassemia syndromes of comparable severity.

38. Hereditary Persistence of Fetal Hemoglobin
(HPFH)
• Deletional
• Pancellular Hb F production
• Ex: Ghanian
• Non-deletional
• Heterocellular Hb F production
Kleihaur Betke Test

39. Thank You 💐