what is beta thalassaemia minor for family physician final

8/3/2019 What is Beta Thalassaemia Minor for Family Physician Final

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What Should One Know About Thalassaemia Minor

WhatIsThalassaemia?

§

Thalassaemiaisacommoninheritedgeneticdisorderofhemoglobin(Hb).§ TounderstandThalassaemiaoneshouldknowabitmoreaboutHbanditsStructure&function.

UnderstandingBLOOD&ItsComponents?

§ TheOxygenfromlungiscarriedtotissuesbyamoleculecalledHemoglobin

§ HemoglobinispackedinRedCells.

§ BesidesRedcells(RBC)ourBloodalsocontainsWhitebloodcells(WBC)andPlatelets.§ TheWBCsareourdefensecellsandtheyhelpusfightinfections.

§ Platelets:aretinycellsthathelpclotbloodalongwithothercoagulationfactors.

§ TheliquidportionofBloodiscalledplasma.

WhatIsHemoglobin?

§ Hemoglobin(Hb)ispinkredincolor&itcarriesOxygenfromlungstotissues.

§ RBClifeis120daysandourBoneMarrowdailyproduces>200billionRBCstoreplace0.8%of

Bloodlostdaily.

§ TounderstandthenatureofdefectinthalassaemiaonehastounderstandthestructureofHB.

TellUsAboutStructureOfHemoglobin?

§ ThestructureofHBresemblesatransportvehicle.

§ HemeformsthecentreofHb&isverysimilartothechassisofavehicle;

§ Thefront&backwheelsareproteinattachmentscalledalpha&Betachain(Seefig1).

§ All components aremanufactured by genes at different sites and finallyassembled to form

completeHbmoleculeseefig1.

HowIsHemoglobinManufacturedInOurBody?

§ αchain,βchainandhemearemanufacturedatdifferentsitesintheerythroidcellsandfinally

assembledintoacompleteHBmolecule.

§ Foralphachainswehave4genes (αα /αα )seefig1.

§ Whileforbetageneswehave2genes (β/β)seefig1.§ Halfofthesegeneswereceivefromourmotherandhalffromfatherasshownin fig1.

WhatIsTheDefectInThalassaemia?

§ Thalassaemiaisbasicallyaquantitativedefectofthesechains.§ Thosewithan α chaindefectsarecalledα Thalassaemia.

§ Thosewithβ chaindefectsarecalledβ Thalassaemia.

WhatistheGeneticofThalassaemia?

§ Thalassaemiaisageneticdefectacquiredatbirth.

§ Oneisbornwithitandwillcarrythisdefectthroughoutone’slife.

§ Youcanalsopassonthisdefecttoyourchildren



(Fig.1)Hemoglobinmoleculesimplifiedstructure&inheritanceofalphaandbetachainof

hemoglobin.

WhatAreTheClinicalTypesOfThalassaemia?

§ ClinicaltypesofβThalassaemia:

o βThalassaemiaMinor:milddefectinwhichoneoutoftwo βchaingeneisdefective.

i.e.onegoodgeneandonebadgene. (β/-)seefig2.n βThalassaemiamajor:severedefectinwhichboththeβ chaingeneisdefective

(-/-)Bothβgenesdefective

ChildrenbornwithThalassaemiamajorneedslifelongbloodtransfusiontosurvive.

“Knowledge about thalassaemia is important to prevent the birth of a child with thalassaemiamajor.”



Fig2:showthedefectinβThalassaemiaMinorwherethereisquantitativedefectinone βchain.

Fig3:showthedefectinβThalassaemiaMajorwherethereisquantitativedefectinboth βchains.



WhatIsTheMagnitudeOfProblem?

§ ThalassaemiaminorisextremelycommoninIndiaandthesouthEastAsiancountriesandthe

Mediterraneancountries.

§ Therewouldbemorethan30millionscasesofthalassaemiaminorortraitsinourcountry.

§ Thalassaemia minor is more common among certain communities like Lohanas, Kutcchis,

Sindhis, Bhanushalis, Khojas, Jains, Neobuddhists, Bhatias, Punjabis, agarwals, Muslims,Bengalisandvarioustribalgroupsthoughalmostanybodycouldhavethisgeneticdefect.

§ Theprevalencerateofβ ThalassaemiaMinoramongcertaincommunitiesmayvaryfrom1%

to5%.

§ Everyyearmorethan10,000childrenwiththalassaemiamajorareborninourcountry.

ThalassaemiaMinorOrThalassaemiaCarrierHowDoWeIdentifyThem?

§ βThalassaemiaMinor isoftenasymptomatic.

§ βThalassaemiaMinormayberecognizedwhenthereisachildwiththalassaemiamajorborn

inthefamily.

§ βThalassaemiaminormaypresentwithmildrefractoryanemia(HBbetween9to11gm/dl)

§ Exaggerationofanemiaduringpregnancy.§ IntheCBCreportofanindividual;ifRBCcountis>5.0millionwithmildanemiaorifMCV/RBC

ratiois<11itfavorsβThalassaemiaMinor.

HowDoesOneDiagnoseβThalassaemiaMinor?

§ DoHBelectrophoresis.HbA2valueof>3.5confirm βThalassaemiaminor.

§ PreferablydoHbElectrophoresisbyHPLCforaccuratevaluesofHbA2

§ Inhigh-riskcommunitiesscreeningforβthalassaemiaminorisveryrewarding,especiallyinthe

marriageableagegroup.

WhatIsTheImplicationOfDiagnosisOfβThalassaemiaMinorForAnIndividual?

§ Anindividualwithβ ThalassaemiaminorhasmildanemiawithHbinrangeof9 to11gm/dl.Whichisoftenunrecognized

§ Thereisnoeffectonhislifespanorhisroutineactivity.

§ Anemiamaygetexaggeratedtemporarilyduringpregnancy.

§ Themostimportantimplicationisgenetic.

GeneticCounseling:

§ IfBothHusbandAndWifeAreThalassaemiaMinorThePossibilitiesAreShownInFig4.

o Thereis25%ofhavingachildwithThalassaemiaMajor

o 25%chanceofchildbeingNormal

o 50%chanceofchildbeingThalassaemiaMinor

§ IfOneOfThePartnersIsThalassaemiaMinorAndOneOfThemIsNormalThePossibilities

AreShownInFig5.

o 50%chanceofchildbeingNormal.

o 50%chanceofChildhavingβThalassaemiaMinor.



Fig4:PossibilitieswhenbothparentsarebThalassaemiaMinor

Fig5:PossibilitieswhenoneparentisNormal&otherparentis β ThalassaemiaMinor



HowCanWePreventTheBirthOfChildWithThalassaemiaMajor?

§ If you are from one ofthe high-risk communities Test your self for thalassaemiaminor

beforemarriage.

§ If you have thalassaemia minor then test your spouse and other family members for

thalassaemiaminor.

§ IfbothHusbandandwifehavethalassaemiaminor,foreverypregnancy,theyshouldgofor

antenataldiagnosistofindoutwhetherthechildtobebornisnormal,minorormajor.Incase the test show the fetus to be thalassaemia major then a decision regarding

continuationofpregnancyhastobemade.§ TheseantenataltestsareavailableinvariouscentersinIndia

§ Detailsabouttheantenataldiagnosiscanbefoundat www.thalassaemia.org

ThalassaemiaMajor:

§ Everyyeartherearemorethan10,000childrenwiththalassaemiamajorborninIndia.

§ Indiahasmorethan100,000casesofthalassaemiamajor.

§ Children bornwithThalassaemiamajor as thename suggestshas amajor problemwith

defectsinboththeßgenes.

§ Most are symptomatic by the age of 1 to 2 yearswith severe anemia, liver and spleen

enlargementandbonychanges.

§ Theyneedlifelongbloodtransfusionfortheirsurvival.

§ Bloodtransfusionisrequiredonceevery3to4weekstoalwaysmaintainHBabove9to10.5

gm/dl.

§ Lifelong blood transfusion has its own problems like Tx reactions, transmission of viral

infectionslikeHIV,HbsAG,HCV,otherviruses;Ironoverload.

§ Everyunitoftransfusiongivesthechildapproximately200to250mgofelementaliron

§ Bodydonothaveanyeffectivemeansofexcretingironhenceironaccumulationoccursin

variousorgansofthebodylikeliver,heart,Testes,pancreas,joints,parathyroid,thyroid,

Skinresultingindamagetotheseorgans.

§ Deathgenerallyissecondarytoheartandorliverfailure.

§ To remove excess iron from the body these children need to take some form of iron

chelationwitheitherdesferalorKelferorAsunra,whichalsohasitsownproblem.§ Some children the need for blood transfusion increases dramatically due to hyper

functioningspleeninwhichcasesplenectomywillhelpthechild.

§ Thesechildrenneedpsychologicalsupportfromdoctor,familyandprofessionalhelpwhen

necessary.

§ Themediansurvivalofachildwiththalassaemiamajorinourcountryisapproximately15to

20years.

§ Thesurvivalrateisimprovingandinstancesofthalassaemiamajorchildrenhavingattained

adulthood,marriedandhavingtheirownchildrenareseenmorefrequently.

§ Hopeandpositiveattitudeisofgreathelp.

CanWeCureThalassaemiaMajor?

§ TheonlycurativetreatmentisBoneMarrowTransplantation(BMT).

§ BMTcostsapproximately8to10lakhsofrupeesandacompletelymatchedsiblingdonor

forBMstemcells.

§ Thereisnorisktothedonor

§ Alternativesourceforstemcellsisumbilicalcordblood.

§ ThesuccessratewithBMTincompletelymatchedsiblingdonorisalmost80%

§ Thesuccessratedecreaseswithadvancedliverdiseaseintherecipient,ifitisamatchedbut

unrelateddonor.



AreThereAnyResearchTreatmentsAvailable?

§ ThereistremendousresearchinterestinGenetherapy.

§ Sincethalassaemiaoccursbecauseofadefectivegeneitispossibletoreplacethisabnormal

geneandthechildcanbecured.

§ Thisisthefuturetreatmentandexpectationsareveryhigh.

§ Genetherapyshouldbecomeavailablebynextdecade.

PointsToRemember;“ClinicalPearls”

§ Therearemorethan30millionthalassaemiaminorcarriersinIndia

§ Youcouldbeoneofthem.Itisnotataboo

§ DoatestforThalassaemiaminorevenifyouappeartobehealthyespeciallyifyoubelongto

high-riskcommunity.

§ Ifyouhavethalassaemiaminorcheckwhetheryourspouse/spousetobeisathalassaemia

minor.

§ Ifbothyouandyourspousehavethalassaemiaminor,doaprenataltestbychorionicvillous

samplingveryearlyinpregnancy.§ Ouraimshouldbetopreventthebirthofchildwiththalassaemiamajor

§ Spreadawarenessaboutthalassaemia.

§ ChildrenafflictedwithThalassaemiaMajorneedourcompassionandsupport.

§ AllDoctorshaveanobligationtoSocietytopickuptelltalesigns,whichsuggestpresence

of β Thalassaemia Minor on CBC report, like an RBC count > 5.0 million suggesting

ineffectiveerythropoiesis;&MCV/RBCRatio<11favoringthepossibilityofβThalassaemia

Minor.

Dr Mukesh M Desai. M.D Prof. of Pediatric Hematology Oncology (DNB)Hon. Hematologist Oncologist & Immunologist.

Department of PHO.Division Chief, Immunology;B. J. Wadia Hospital for Children.

Honorary Consultant HematologistNanavati Hospital.Sir H N Hospital.Saifee Hospital. Asian Heart Institute

Rooms:

Hematology & Immunology Cell.B1 Matru Ashish,Next to Balbharti School; SV Road,Kandivili west, Mumbai 400067.

Cell : +91 9820037087.Clinic : +91 22 28092927;

+91 22 28092917.

Email: [email protected] URL: http://sites.google.com/site/mmdesai007/

what is beta thalassaemia minor for family physician final

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