1 / 24

Haemoglobin

Haemoglobin. 4 globin chains each with 1 Haem 3 main haemoglobins Hb A Alpha2 Beta2 Hb A2 Alpha2 delta2 Hb F Alpha2 Gamma2 Main purpose to carry O2 --- Haem part

xannon
Télécharger la présentation

Haemoglobin

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Haemoglobin 4 globin chains each with 1 Haem 3 main haemoglobins Hb A Alpha2 Beta2 Hb A2 Alpha2 delta2 Hb F Alpha2 Gamma2 Main purpose to carry O2 --- Haem part Amino acid sequence critical with variations leading to alterations in O2 carrying solubility integrity

  2. Haemoglobin 2 Critical Locations Alpha1 beta2 contact --- O2 affinity Prox & distal Histidine of Haem pocket --- Haem oxidation – HbM Haem contact areas --- globin instability unstable HbS

  3. Haemoglobinopathies Quantitative --- normal chain def. Thalasaemias Qualitative ---- Abn chains (amino acids) Altered solubility HbS HbC Instability Unstable Hb Altered O2 Affinity Increased Chesapeake Kempsey Decreased Seattle Cyanosis HbM

  4. Thalassaemias • Deficiency / absence normal chain. No abnormal chain present • Named by missing chain Alpha Thal Alpha chain missing Beta Thal Beta chain missing • Autosomal dominant trait though heterozygotes have minimal difficulty • RNA/DNA defect in regulator gene function with resultant def of messenger RNA

  5. Beta Thalassaemia • Defective Beta chain formation, partial or complete • Mechanism of anaemia Inneffective erythropoesis Decreased RBC survival (haemolysis) Defective Hb formation

  6. Beta Thalassaemias • Clinical Types / features Thal minor Asymptomatic Hypochromic microcytic anaemia. Target cells Thal intermedia Thal Major Severe anaemia Tx dep. Spleen +++

  7. Beta Thalassaemia • Haemoglobin studies Thal minor --- incr slight incr A2 Thal major --- markedly incr F 30-90%

  8. Sickle cell disease HbS • Single amino acid substitution Beta 6 Glutamic Acid  Valine (HbC is Beta 6 Glu  Lycine) • Change alters the solubility of HbS causing it to come out of solution in esp when deoxygenated

  9. Beta Thalassaemia • Therapy / prognosis Blood Folic acid Iron chelation Splenectomy

More Related