What Shuld One Knw Abut Thalassaemia Minr What Is Thalassaemia? Thalassaemia is a cmmn inherited genetic disrder f hemglbin (Hb). T understand Thalassaemia ne shuld knw a bit mre abut Hb and its Structure & functin. Understanding BLOOD & Its Cmpnents? The Oxygen frm lung is carried t tissues by a mlecule called Hemglbin Hemglbin is packed in Red Cells. Besides Red cells (RBC) ur Bld als cntains White bld cells (WBC) and Platelets. The WBCs are ur defense cells and they help us fight infectins. Platelets: are tiny cells that help clt bld alng with ther cagulatin factrs. The liquid prtin f Bld is called plasma. What Is Hemglbin? Hemglbin (Hb) is pink red in clr & it carries Oxygen frm lungs t tissues. RBC life is 120 days and ur Bne Marrw daily prduces > 200 billin RBCs t replace 0.8% f Bld lst daily. T understand the nature f defect in thalassaemia ne has t understand the structure f HB. Tell Us Abut Structure Of Hemglbin? The structure f HB resembles a transprt vehicle. Heme frms the centre f Hb & is very similar t the chassis f a vehicle; The frnt & back wheels are prtein attachments called alpha & Beta chain (See fig 1). All cmpnents are manufactured by genes at different sites and finally assembled t frm cmplete Hb mlecule see fig 1. Hw Is Hemglbin Manufactured In Our Bdy? α chain, β chain and heme are manufactured at different sites in the erythrid cells and finally assembled in t a cmplete HB mlecule. Fr alpha chains we have 4 genes (αα / αα) see fig 1. While fr beta genes we have 2 genes (β/ β) see fig 1. Half f these genes we receive frm ur mther and half frm father as shwn in fig 1. What Is The Defect In Thalassaemia? Thalassaemia is basically a quantitative defect f these chains. Thse with an α chain defects are called α Thalassaemia. Thse with β chain defects are called β Thalassaemia. What is the Genetic f Thalassaemia? Thalassaemia is a genetic defect acquired at birth. One is brn with it and will carry this defect thrugh ut ne s life. Yu can als pass n this defect t yur children
(Fig. 1) Hemglbin mlecule simplified structure & inheritance f alpha and beta chain f hemglbin. What Are The Clinical Types Of Thalassaemia? Clinical types f β Thalassaemia: β Thalassaemia Minr: mild defect in which ne ut f tw βchain gene is defective. i.e. ne gd gene and ne bad gene. (β /- ) see fig 2. n β Thalassaemia majr: severe defect in which bth the β chain gene is defective (- / - ) Bth β genes defective Children brn with Thalassaemia majr needs life lng bld transfusin t survive. Knwledge abut thalassaemia is imprtant t prevent the birth f a child with thalassaemia majr.
Fig 2: shw the defect in β Thalassaemia Minr where there is quantitative defect in ne β chain. Fig 3: shw the defect in β Thalassaemia Majr where there is quantitative defect in bth β chains.
What Is The Magnitude Of Prblem? Thalassaemia minr is extremely cmmn in India and the suth East Asian cuntries and the Mediterranean cuntries. There wuld be mre than 30 millins cases f thalassaemia minr r traits in ur cuntry. Thalassaemia minr is mre cmmn amng certain cmmunities like Lhanas, Kutcchis, Sindhis, Bhanushalis, Khjas, Jains, Nebuddhists, Bhatias, Punjabis, agarwals, Muslims, Bengalis and varius tribal grups thugh almst anybdy culd have this genetic defect. The prevalence rate f β Thalassaemia Minr amng certain cmmunities may vary frm 1 % t 5 %. Every year mre than 10,000 children with thalassaemia majr are brn in ur cuntry. Thalassaemia Minr Or Thalassaemia Carrier Hw D We Identify Them? β Thalassaemia Minr is ften asymptmatic. β Thalassaemia Minr may be recgnized when there is a child with thalassaemia majr brn in the family. β Thalassaemia minr may present with mild refractry anemia (HB between 9 t 11 gm/dl) Exaggeratin f anemia during pregnancy. In the CBC reprt f an individual; if RBC cunt is > 5.0 millin with mild anemia r if MCV/RBC rati is < 11 it favrs β Thalassaemia Minr. Hw Des One Diagnse β Thalassaemia Minr? D HB electrphresis. HbA2 value f > 3.5 cnfirm β Thalassaemia minr. Preferably d Hb Electrphresis by HPLC fr accurate values f HbA2 In high- risk cmmunities screening fr β thalassaemia minr is very rewarding, especially in the marriageable age grup. What Is The Implicatin Of Diagnsis Of β Thalassaemia Minr Fr An Individual? An individual with β Thalassaemia minr has mild anemia with Hb in range f 9 t 11 gm / dl. Which is ften unrecgnized There is n effect n his life span r his rutine activity. Anemia may get exaggerated temprarily during pregnancy. The mst imprtant implicatin is genetic. Genetic Cunseling: If Bth Husband And Wife Are Thalassaemia Minr The Pssibilities Are Shwn In Fig 4. There is 25% f having a child with Thalassaemia Majr 25% chance f child being Nrmal 50% chance f child being Thalassaemia Minr If One Of The Partners Is Thalassaemia Minr And One Of Them Is Nrmal The Pssibilities Are Shwn In Fig 5. 50% chance f child being Nrmal. 50% chance f Child having β Thalassaemia Minr.
Fig 4: Pssibilities when bth parents are b Thalassaemia Minr Fig 5: Pssibilities when ne parent is Nrmal & ther parent is β Thalassaemia Minr
Hw Can We Prevent The Birth Of Child With Thalassaemia Majr? If yu are frm ne f the high- risk cmmunities Test yur self fr thalassaemia minr befre marriage. If yu have thalassaemia minr then test yur spuse and ther family members fr thalassaemia minr. If bth Husband and wife have thalassaemia minr, fr every pregnancy, they shuld g fr antenatal diagnsis t find ut whether the child t be brn is nrmal, minr r majr. In case the test shw the fetus t be thalassaemia majr then a decisin regarding cntinuatin f pregnancy has t be made. These antenatal tests are available in varius centers in India Details abut the antenatal diagnsis can be fund at www.thalassaemia.rg Thalassaemia Majr: Every year there are mre than 10,000 children with thalassaemia majr brn in India. India has mre than 100,000 cases f thalassaemia majr. Children brn with Thalassaemia majr as the name suggests has a majr prblem with defects in bth the ß genes. Mst are symptmatic by the age f 1 t 2 years with severe anemia, liver and spleen enlargement and bny changes. They need life lng bld transfusin fr their survival. Bld transfusin is required nce every 3 t 4 weeks t always maintain HB abve 9 t 10.5 gm/dl. Lifelng bld transfusin has its wn prblems like Tx reactins, transmissin f viral infectins like HIV, HbsAG, HCV, ther viruses; Irn verlad. Every unit f transfusin gives the child apprximately 200 t 250 mg f elemental irn Bdy d nt have any effective means f excreting irn hence irn accumulatin ccurs in varius rgans f the bdy like liver, heart, Testes, pancreas, jints, parathyrid, thyrid, Skin resulting in damage t these rgans. Death generally is secndary t heart and r liver failure. T remve excess irn frm the bdy these children need t take sme frm f irn chelatin with either desferal r Kelfer r Asunra, which als has its wn prblem. Sme children the need fr bld transfusin increases dramatically due t hyper functining spleen in which case splenectmy will help the child. These children need psychlgical supprt frm dctr, family and prfessinal help when necessary. The median survival f a child with thalassaemia majr in ur cuntry is apprximately 15 t 20 years. The survival rate is imprving and instances f thalassaemia majr children having attained adulthd, married and having their wn children are seen mre frequently. Hpe and psitive attitude is f great help. Can We Cure Thalassaemia Majr? The nly curative treatment is Bne Marrw Transplantatin (BMT). BMT csts apprximately 8 t 10 lakhs f rupees and a cmpletely matched sibling dnr fr BM stem cells. There is n risk t the dnr Alternative surce fr stem cells is umbilical crd bld. The success rate with BMT in cmpletely matched sibling dnr is almst 80 % The success rate decreases with advanced liver disease in the recipient, if it is a matched but unrelated dnr.
Are There Any Research Treatments Available? There is tremendus research interest in Gene therapy. Since thalassaemia ccurs because f a defective gene it is pssible t replace this abnrmal gene and the child can be cured. This is the future treatment and expectatins are very high. Gene therapy shuld becme available by next decade. Pints T Remember; Clinical Pearls There are mre than 30 millin thalassaemia minr carriers in India Yu culd be ne f them. It is nt a tab D a test fr Thalassaemia minr even if yu appear t be healthy especially if yu belng t high- risk cmmunity. If yu have thalassaemia minr check whether yur spuse / spuse t be is a thalassaemia minr. If bth yu and yur spuse have thalassaemia minr, d a prenatal test by chrinic villus sampling very early in pregnancy. Our aim shuld be t prevent the birth f child with thalassaemia majr Spread awareness abut thalassaemia. Children afflicted with Thalassaemia Majr need ur cmpassin and supprt. All Dctrs have an bligatin t Sciety t pick up tell tale signs, which suggest presence f β Thalassaemia Minr n CBC reprt, like an RBC cunt > 5.0 millin suggesting ineffective erythrpiesis; & MCV/RBC Rati < 11 favring the pssibility f β Thalassaemia Minr. Dr Mukesh M Desai. M.D Prf. f Pediatric Hematlgy Onclgy (DNB) Hn. Hematlgist Onclgist & Immunlgist. Department f PHO. Divisin Chief, Immunlgy; B. J. Wadia Hspital fr Children. Hnrary Cnsultant Hematlgist Nanavati Hspital. Sir H N Hspital. Saifee Hspital. Asian Heart Institute Rms: Hematlgy & Immunlgy Cell. B1 Matru Ashish, Next t Balbharti Schl; SV Rad, Kandivili west, Mumbai 400067. Cell : +91 9820037087. Clinic : +91 22 28092927; +91 22 28092917. Email: mmdesai007@gmail.cm URL: http://sites.ggle.cm/site/mmdesai007/