Hemoglobinopathy

Hemoglobinopathy Main page
Overview
Classification
Epidemiology and Demographics
Diagnostic approach

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sogand Goudarzi, MD [2]

Overview

Hemoglobinopathy is a kind of genetic defect that results in abnormal structure of one of the globin chains of the hemoglobin molecule. Most common hemoglobinopathies include sickle-cell disease.The renge of clinical manifestations of the hemoglobinopathies are from mild hypochromic anemia to moderate hematological disease to severe.

Classification

Hemoglobinopathy be classified according to genetic and structure of hemoglobin into two main groups:

• Thalassemia syndromes
  • α-thalassemia
  • β-thalassemia
• Structural hemoglobin variants
  • HbS
  • HbE
  • HbC
  • Hb Bart’s
  • Hb J(Johnstown)
  • HbM
  • HbX
  • HbD

Hemoglobinopathy classification

Quantititive disorders of globin chain synthesis

Qualitative disorder of globin structure

α-thalassemia

β-thalassemia

De novo and acquired α-thalassemia

Sickle cell disorders

Hemoglobins with decreased stability (unstable hemoglobin variants)

Hemoglobins with altered oxygen affinity

Methemoglobin

Posttranslational modifications

Delitation of α globin

α-Thalassemia with mental retardation syndrome (ATR)

SA, sickle cell trait

Mutants causing congenital Heinz body hemolytic anemia

High/increased oxygen affinity states

Congenital methemoglobinemia

Nonenzymatic glycosylation

Low/decreased oxygen affinity states

Amino-terminal acetylation

Nondeletion mutants

α-Thalassemia associated with myelodysplastic syndromes (ATMDS)

SS, sickle cell anemia/disease

Acquired instability—oxidant hemolysis

Amino-terminal carbamylation

Drug-induced

Deamidation

G6PD deficiency

SC, HbSC disease

S/β thal, sickle β-thalassemia disease

S with other Hb variants: D, O-Arab, other

SF, Hb S/HPFH

Clinical classification

Biochemical/genetic classification

Structural variants with β-thalassemia phenotype

Minor/trait

Intermediate

Major

β0 thalassemia

β0 thalassemia

δ thalassemia

γ thalassemia

Lepore fusion gene

HbS/β-thalassemia

HbE/β-thalassemia

Other

δβ-Thalassemia

εγδβ-Thalassemia

HPFH

The range of clinical manifestations of the hemoglobinopathies are from mild hypochromic anemia to moderate hematological disease to severe.

Differentiating between Hemoglobinopathies

				Gene type	Red blood cell (RBC) count g/dl		Hemoglobin pattern	Differentiating Symptoms
					Hemoglobin g/dl	MCH /pg
Alpha Thalassemia				-+/++	Normal	Normal	Normal	None
				-+/-+ --/++	Normal or low	<26	Normal	Mild anemia
				--/-+	8 to 10	<22	HbH 10 to 20%	Chronic hemolytic anemia
				Hb Bart’s hydrops fetalis --/--	<6	<20	Hb Bart’s 80 to 90%, Hb Portland 10 to 20%, HbH <1%	Life-threatening fetal anemia
β-thalassemia	Heterozygous			&β/++	9 to 15
				&β/+-
				&β/--
	Compound heterozygous			&beta; + /&beta; 0
	Homozygous			&beta;+/&beta;+	<7
				&beta; 0 /&beta; 0
Sickle cell Disease					6 to 9
HBC

Epidemiology and Demographics

Incidence

• The incidence/prevalence of [disease name] is approximately [number range] per 100,000 individuals worldwide.
• In [year], the incidence/prevalence of [disease name] was estimated to be [number range] cases per 100,000 individuals worldwide.

Prevalence

• In 2008, the prevalence of hemoglobinopathy was estimated to be 7% of the worldwide population being carrier.
• The most prevalance of hemoglobinopathy gene carriers in the world's are in South-East Asia(up to 70%) and Arab nations(up to 60).
• In Russia is seen rare
• Recent years is increased in Germany.

Race

α-thalassemias

It occure cur mainly in Africa, Arab nations, and, more frequently and South-East Asia.

β-thalassemias

It occure cur mainly in Mediterranean countries, South-East Europe, Arab nations and Asia.

Diagnosis

Hemoglobin testing(hemoglobin electrophoresi or chromatography) , red blood cell count, hemoglobin pattern, cardinal symptoms

Hemoglobinopathy

History & clinical symptoms

Hemolystate

Blood count, including RBC morphology

Diagnosis of abnormal hemoglobin

Diagnosis of β-thalassemia

Diagnosis of α-thalassemia

References

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