1. HEREDITARY HAEMOLYTIC ANAEMIAS HEREDITARY HAEMOLYTIC ANAEMIAS BY DR. FATMA ALQAHTANI CONSULTANT HAEMATOLOGIST HEREDITARY SPHEROCYTOSIS

3. HEREDITARY HAEMOLYTIC ANAEMIA MEMBRANE DEFECTS MEMBRANE DEFECTS * Hereditary Spherocytosis * Hereditary Spherocytosis * Hereditary Elliptocytosis * Hereditary Elliptocytosis * Hereditary Stomatocytosis * Hereditary Stomatocytosis etc …. etc ….

4. HEREDITARY HAEMOLYTIC ANAEMIA METABOLIC DEFECTS: METABOLIC DEFECTS: Deficiency of: Deficiency of: * Glucose-6-phosphate dehydrogenase * Glucose-6-phosphate dehydrogenase * Pyruvate kinase * Pyruvate kinase * Triose phosphate isomerase * Triose phosphate isomerase * Pyrimidine-5-nucleotidase * Pyrimidine-5-nucleotidase * Glutathione synthetase * Glutathione synthetase etc …. etc ….

5. HEREDITARY HAEMOLYTIC ANAEMIA HAEMOGLOBIN DEFECTS: HAEMOGLOBIN DEFECTS: * Defective synthesis * Defective synthesis e.g. Thalassaemia (Alpha or Beta) e.g. Thalassaemia (Alpha or Beta) * Abnormal variants * Abnormal variants e.g. Hb S, Hb C, Unstable Hb e.g. Hb S, Hb C, Unstable Hb

6. GENETIC ABNORMALITIES OF THE RED CELL MEMBRANE Hereditary Spherocytosis Hereditary Spherocytosis Hereditary Elliptocytosis Hereditary Elliptocytosis Hereditary Stomatocytosis Hereditary Stomatocytosis Hydrocytosis (high MCV, low MCHC) Hydrocytosis (high MCV, low MCHC) Xerocytosis (low MCV, high MCHC shrunken RBCs due to K loss) Xerocytosis (low MCV, high MCHC shrunken RBCs due to K loss) Acanthocytosis – Abeta-lipoproteinaemia Acanthocytosis – Abeta-lipoproteinaemia

8. GENETIC ABNORMALITIES OF THE RED CELL MEMBRANE HEREDITARY SPHEROCYTOSIS (HS) NAMEElectrophoretic Band * Molecular weight (kd) Number of molecules / RBC ( x 10 5 ) Location / function ChromosomalAssignmentGenecloned αSpectrin β β124022 CS: form heterodimers, tetramers 1 q22 – 1 q25 Yes 2220Yes Actin5425 Cs: forms protofilaments of 10-13 monomers 7 pter – q22 Yes ‘ Band ‘ 4.1782 Crosslinks spectrin heterodimers 1 p32 – 1 pter Yes Ankyrin2.12101 Links spectrin to band 3 ‘ Band ‘ 39510 IMP: anion transport: links to ankyrin Glycophorin A PASI, 2 294 IMP: sialoglycoprotein 4 q28 Yes IMP = integral membrane protein CS = cytoskeleton * as currently numbered on SDS – gels

9. PATHOGENESIS OF HEREDITARY SPHEROCYTOSIS (HS) ? Spectrin genes genes ? Gene for other membrane protein Abnormal Abnormal spectrin spectrin DecreasedSynthesis of spectrin Decreased binding of spectrin Decreased spectrin in membrane Spherocytes OF Glucoserequirement Decreased Decreaseddeformability

10. HEREDITARY SPHEROCYTOSIS (HS) DEFINITION: DEFINITION: A congenital disorder which is characterized by: A congenital disorder which is characterized by: * spherocytes * spherocytes * increased osmotic fragility * increased osmotic fragility * autosomal dominant inheritance ( ! recessive ) * autosomal dominant inheritance ( ! recessive ) * beneficial response to splenectomy * beneficial response to splenectomy

11. HEREDITARY SPHEROCYTOSIS (HS) The diagnosis of HS is not always easy since: * The degree of spherocytosis is variable * The degree of spherocytosis is variable * The changes in osmotic fragility are not always clear cut * The changes in osmotic fragility are not always clear cut * Sporadic cases can occur * Sporadic cases can occur * Other haemolytic anaemias may respond to splenectomy * Other haemolytic anaemias may respond to splenectomy

12. HEREDITARY SPHEROCYTOSIS (HS) Role of spleen: Role of spleen: * Results post splenectomy * Results post splenectomy - Decrease in the rate of haemolysis (ameliorates the degree of anaemia) - Decrease in the rate of haemolysis (ameliorates the degree of anaemia) - Decrease in the number of spherocytes - Decrease in the number of spherocytes (but can not cure the red cell abnormality) (but can not cure the red cell abnormality) * Spleen is the major site of red cell destruction * Spleen is the major site of red cell destruction * RBCs retained for long time in the splenic pulp as a result of decreased deformability * RBCs retained for long time in the splenic pulp as a result of decreased deformability+ Unfavorable environmental conditions in the splenic pulp (acid pH & decreased glucose) Unfavorable environmental conditions in the splenic pulp (acid pH & decreased glucose) Failure of the cation pump Loss of water Loss of RBCs discoid shape Vicious circle

13. HEREDITARY SPHEROCYTOSIS (HS) Clinical Manifestations: Most of the cases present in childhood or as teenagers Most of the cases present in childhood or as teenagers HS has been rarely diagnosed at: HS has been rarely diagnosed at: * Neonatal period (persistent jaundice) * Neonatal period (persistent jaundice) * The age of 60 (asymptomatic) * The age of 60 (asymptomatic) The disease has a wide spectrum of severity The disease has a wide spectrum of severity The most consistent findings according to frequency are: The most consistent findings according to frequency are: * Jaundice * Jaundice * Splenomegaly * Splenomegaly * Anaemia * Anaemia

14. HEREDITARY SPHEROCYTOSIS (HS) Clinical Manifestations (cont … ): Haemolysis can be compensated for, with normal Haemolysis can be compensated for, with normal haemoglobin in about 1/3 of the patients haemoglobin in about 1/3 of the patients Patients may be more yellow than sick Patients may be more yellow than sick Cholelithiasis is a complication of HS Cholelithiasis is a complication of HS HS as any other congenital haemolytic anaemia has a HS as any other congenital haemolytic anaemia has a STEADY STATE and EPISODIC CHANGES STEADY STATE and EPISODIC CHANGES

15. HEREDITARY SPHEROCYTOSIS (HS) Laboratory Tests and Findings: *Peripheral blood film\ > 1-2% spherocytes in significant *MCHC is increased or in the upper limit of normal range (due to decreased water content) *Increased osmatic fragility (O.F) Shift to the right of the entire curve or only part of it Draw backs of this test: -Laborious test -Needs fresh defibrinated blood -Not specific for HS (can be increased in AIHA) -Insufficiently sensitive (10-25%) of patients genetically proven to have HS have normal O.F) *Acidified glycerol lysis time. The rate of haemolysis (The time required for 50% lysis). Normal values > 1800 seconds) *Auto haemolysis (Screening test). 48 hours incubation under sterile conditions

16. HEREDITARY SPHEROCYTOSIS (HS) Spherocytes

17. HEREDITARY ELLIPTOCYTOSIS (HE) Elliptocytes

18. HEREDITARY STOMATOCYTOSIS (HST) Stomatocytes

19. HEREDITARY SPHEROCYTOSIS

20. HEREDITARY SPHEROCYTOSIS (HS) Autohaemolysis Test Lysis in a typical case (%) No addition + 27 mmol glucose No addition + 27 mmol glucoseCondition 0.151.7Normal 1.310.1 Hereditary spherocytosis 6.15.5 Pyruvate kinase deficiency 1.82.9 G6PD deficiency with CNSHA * * In the more common forms of G6PD deficiency without chronic non spherocytic haemolytic anaemia (CNSHA) the autohaemolysis test is normal

21. HEREDITARY SPHEROCYTOSIS (HS) Differential diagnosis IF SPHEROCYTOSIS is prominent: IF SPHEROCYTOSIS is prominent: Acquired haemolytic anaemia DAT DAT FAMILY DATA Red cell fragmentation favours poikilocytosis microangiopathic process Fever may favor rare infectious cause for haemolysis (Clostridium welchii) IF SPHEROCYTOSIS is not prominent with chronic course: IF SPHEROCYTOSIS is not prominent with chronic course: PNH ---- Ham test Enzymopatheis ---- O.F. usually normal or decreased Autohaemolysis not corrected by glucose Autohaemolysis not corrected by glucose

22. HEREDITARY SPHEROCYTOSIS (HS) Complications Leg ulcers Leg ulcers Gall stones (Often asymptomatic) Gall stones (Often asymptomatic) Aplastic crises Aplastic crises

23. HEREDITARY SPHEROCYTOSIS (HS) Management No cure No cure The aim is to minimize the consequences of the genetic abnormality The aim is to minimize the consequences of the genetic abnormality Splenectomy Splenectomy Avoid below the age of 5 years unless haemolytic anaemia is very severe (rare is HS) Pneumococcal vaccination – (regular penicillin for at least 2 years) Pneumococcal vaccination – (regular penicillin for at least 2 years) Treatment of complication ’ s as arises Treatment of complication ’ s as arises

24. Different forms of elliptocytosis Remarks Example of known molecular lesion Degree of haemolysis Genetic status Sub type of hereditary elliptocytosis (HE) One parent has similar picture Structurally abnormal α – spectrin AbsentHeterozygote Common Non- haemolytic One parent has similar picture Glycoprotein C deficiency MinimalHeterozygoteMild One parent has similar picture ModerateHeterozygoteIntermediate One parent has HE: some times both SevereHeterozygoteSevere Usuallybot parents asymptomatic. Or one has HE Structurally abnormal α – spectrin SevereHomozygote Pyropoikilocyt osis Deletion revealed at DNA level (Conoboy et al., 1986) Absence of protein 4.1 MildSevere Heterozygote Homozygote Spherocytic Common in Melanesians ? Protects against malaria Absent or mild Not well defined Stomatocytic