Rev. Bras. Hematol. Hemoter. vol.38 número3

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rev bras hematol hemoter. 2016;38(3):188–189

w w w . r b h h . o r g

Revista

Brasileira

de

Hematologia

e

Hemoterapia

Brazilian

Journal

of

Hematology

and

Hemotherapy

Scientific

Comment

Compound

heterozygosity

for

hemoglobin

S

and

D:

what

do

we

need

to

know?

夽

Claudia

Regina

Bonini-Domingos

∗

UniversidadeEstadualPaulistaJúliodeMesquitaFilho(UNESP),SãoJosédoRioPreto,SP,Brazil

Hemoglobinopathiesare among the mostcommon

heredi-tary blood diseasesworldwide andare considered a public

healthprobleminsomeregions.InBrazil,hemoglobinS(Hb

S)hasavariablefrequencybetweendifferentregionsmainly

duetothe ethniccomposition oflocalpopulations. Due to

themultiethniccharacteristicsoftheBrazilianpeople,some

regionsreflectscenariosthatallowustoconsiderthe

inher-itanceofthesymptomaticformsofHbS,namelysicklecell

disease (SCD)aserious publichealthproblem. These

clini-callysignificantformsincludethehomozygousinheritance

ofHb S– sicklecell anemia (HbSS), inheritancewith

tha-lassemia,especiallybetathalassemia(HbS/betathalassemia)

andcompoundheterozygotesinwhichHbSisinheritedin

combinationwithanotherhemoglobinvariant;themost

com-moninBrazilareHbSCandHbSD.

Theapplicationofaccuratelaboratorymethodologies

asso-ciatedtoroutinetechniquessuchaselectrophoresisandhigh

pressureliquidchromatography(HPLC)along with

hemato-logicinformationandfamilydataareessentialforthecorrect

identificationofSCDand,consequently,adequateclinicaland

family guidancethat canguaranteeapromisingprognosis.

However,thedifferentiationbetweenHb SSandthe HbSD

profileisnotpossiblebysimpletestssuchaselectrophoresis

inalkalinepHas,intheseconditions,themigrationsofthe

variantsoverlap.Additionalmethodsareneededtoelucidate

this double heterozygosity. Automated systems such as

capillaryelectrophoresis, HPLC cationexchange, isoelectric

DOIoforiginalarticle:http://dx.doi.org/10.1016/j.bjhh.2016.05.002.

夽

SeepaperbyRezendeetal.onpages240–6.

∗ _{Corresponding}_author_at_:_Departamento_de_Biologia,_Laboratório_de_Hemoglobinas_e_Genética_das_Doenc¸as_{Hematológicas.}_Rua_Cristóvão

Colombo,2265,JardimNazareth,15054-000SãoJosédoRioPreto,SP,Brazil.

E-mailaddress:[email protected]

focusing(IEF)andsimplifiedcombinationsofelectrophoretic

systemswithvariationsinthepHareavailable.1,2

Thereiscertainlackofinformationaboutthephenotypic

manifestationsofHbSDanditsvariationsinpublications.In

theliteraturetherearesomereportsofcasesofHbSDwith

microcyticandhypochromicanemia,paincrisesandclinical

complications.3–5_The_presence_of_associated_genetic_factors

maymodulatetheclinicalexpressionandthepresenceof

ele-vatedHbFlevelsandtheco-inheritanceofalphathalassemia,

forexample,shouldbeinvestigated.6_The_correct

identifica-tion ofindividuals and atleast thesuggestion ofpotential

geneticmodulatorsmayassistinestimatingtheresponseto

treatmentusinghydroxyurea(HU).7

Inourlaboratory,1537patientswithSCDfromthe

south-eastern region of Brazil were evaluated and 26 (1.69%)

had the Hb SD profile confirmed by molecular analysis

(polymerasechainreaction-restrictionfragmentlength

poly-morphism).Ofthese,ten(38.46%)individualswereonblood

transfusions and presentedmicrocytosis,hypochromiaand

hemolytic indexesthat suggested clinicallysevere disease.

Regarding clinical manifestations, all 26 patients had 2–5

pain crises within one year that not necessarily required

hospitalization but had to be seen in a follow-up service.

Moreover,thepatientssufferedfromstrokes(2),retinopathies

(3), cardiac insufficiency(3), acutechest syndrome(6),

pul-monaryhypertension(2),cholelithiasis(3),renalfailure(3)and

ulcers(2).

http://dx.doi.org/10.1016/j.bjhh.2016.06.001

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rev bras hematol hemoter. 2016;38(3):188–189

189

The authors of the article “Clinical, hematological and

geneticdatainacohortofchildrenwithhemoglobinSD”in

thisissueoftheRevistaBrasileiradeHematologiae

Hemoter-apia(RBHH)showtheclinicalandhematologicdiversityofa

groupofchildrenwiththisdoubleheterozygosityand

high-lighttheimportanceofthedifferentialdiagnosis.8

Conflicts

of

interest

Theauthordeclaresnoconflictsofinterest.

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diagnosisofthalassemia.IntJnlLabHem.2016.Availablefrom:

http://onlinelibrary.wiley.com/doi/10.1111/ijlh.12527/epdf

2.PanigrahiP,PatraPK,KhodiarPK.Thescreeningandmorbidity

patternofsicklecellanemiainChhattisgarh.IndianJHematol

BloodTransfus.2015;31(1):104–9.

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Theeffectofhydroxyureaoncompoundheterozygotesfor

sicklecell-hemoglobinD-Punjab–asinglecentreexperiencein

easternIndia.PediatrBloodCancer.2014;61(8):1341–6.

8.RezendePV,CostaKS,DominguesJuniorJC,SilveiraPB,

BelisarioAR,SilvaCM,etal.Clinical,hematologicaland

geneticdatainacohortofchildrenwiththehemoglobinSD.