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Alpha chain hemoglobins with electrophoretic mobility similar to that of hemoglobin S in a newborn screening program.

Silva MR, Sendin SM, Araujo IC, Pimentel FS, Viana MB - Rev Bras Hematol Hemoter (2013)

Bottom Line: Two associations with hemoglobin S were found: one with hemoglobin Ottawa and one with hemoglobin St Luke's.Apparently these are the first cases of hemoglobin Ottawa, St Luke's, Etobicoke and the α212 gene described in Brazil.Additional tests are necessary for the correct identification of hemoglobin variants.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade Federal de Minas Gerais - UFMG, Belo Horizonte, MG, Brazil.

ABSTRACT

Objective: To characterize alpha-chain variant hemoglobins with electric mobility similar to that of hemoglobin S in a newborn screening program.

Methods: β(S) allele and alpha-thalassemia deletions were investigated in 14 children who had undefined hemoglobin at birth and an electrophoretic profile similar to that of hemoglobin S when they were six months old. Gene sequencing and restriction enzymes (DdeI, BsaJI, NlaIV, Bsu36I and TaqI) were used to identify hemoglobins. Clinical and hematological data were obtained from children who attended scheduled medical visits.

Results: THE FOLLOWING ALPHA CHAIN VARIANTS WERE FOUND: seven children with hemoglobin Hasharon [alpha2 47(CE5) Asp>His, HbA2:c.142G>C], all associated with alpha-thalassemia, five with hemoglobin Ottawa [alpha1 15(A13) Gly>Arg, HBA1:c.46G>C], one with hemoglobin St Luke's [alpha1 95(G2) Pro>Arg, HBA1:c.287C>G] and another one with hemoglobin Etobicoke [alpha212 84(F5) Ser>Arg, HBA212:c.255C>G]. Two associations with hemoglobin S were found: one with hemoglobin Ottawa and one with hemoglobin St Luke's. The mutation underlying hemoglobin Etobicoke was located in a hybrid α212 allele in one child. There was no evidence of clinically relevant hemoglobins detected in this study.

Conclusion: Apparently these are the first cases of hemoglobin Ottawa, St Luke's, Etobicoke and the α212 gene described in Brazil. The hemoglobins detected in this study may lead to false diagnosis of sickle cell trait or sickle cell disease when only isoelectric focusing is used in neonatal screening. Additional tests are necessary for the correct identification of hemoglobin variants.

No MeSH data available.


Related in: MedlinePlus

Products of PCR and PCR-RFLP for the detection of Hb Hasharon (A & B) andEtobicoke (C)A) Products of biplex gap-PCR for four individuals. Lanes 1 to 4 show ampliconsderived from the wild HBA2 (1803 bp) and LIS genes (2351 bp).Lanes 5 to 8 amplicons from LIS and the -α3.7 hybrid gene (2033bp). Lanes 1 and 5, 2 and 6, 3 and 7, 4 and 8 derive from the same children whoseHBA2 and -α3.7 genes were amplifiedseparatelyB) Products of biplex gap-PCR, shown in Figure A, digested withaqI for the detection of the mutation that encodes HbHasharon. The fragment of 894 pb in lanes 5 and 6 indicates that these childrenhave the mutation that characterizes heterozygous Hb Hasharon in the-α3.7 hybrid geneC) Products of PCR for the HBA1 gene (2213 bp: lanes 1 and 2) andfor the HBA2 gene (2217 bp: lanes 5 and 6) derived from twodifferent individuals. Lanes 3, 4, 7 and 8 correspond to the breakdown products ofsamples 1, 2, 5 and 6, respectively, digested with the endonucleaseBsu36I. Lane 7 shows a child with the mutation that encodes HbEtobicoke: the fragment of 2217 bp is cleaved into two fragments of 1388 and 829bp by Bsu36I.1% agarose gel with ethidium bromide; MM: molecular marker; bp: base pairs; NC:blank control
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f01: Products of PCR and PCR-RFLP for the detection of Hb Hasharon (A & B) andEtobicoke (C)A) Products of biplex gap-PCR for four individuals. Lanes 1 to 4 show ampliconsderived from the wild HBA2 (1803 bp) and LIS genes (2351 bp).Lanes 5 to 8 amplicons from LIS and the -α3.7 hybrid gene (2033bp). Lanes 1 and 5, 2 and 6, 3 and 7, 4 and 8 derive from the same children whoseHBA2 and -α3.7 genes were amplifiedseparatelyB) Products of biplex gap-PCR, shown in Figure A, digested withaqI for the detection of the mutation that encodes HbHasharon. The fragment of 894 pb in lanes 5 and 6 indicates that these childrenhave the mutation that characterizes heterozygous Hb Hasharon in the-α3.7 hybrid geneC) Products of PCR for the HBA1 gene (2213 bp: lanes 1 and 2) andfor the HBA2 gene (2217 bp: lanes 5 and 6) derived from twodifferent individuals. Lanes 3, 4, 7 and 8 correspond to the breakdown products ofsamples 1, 2, 5 and 6, respectively, digested with the endonucleaseBsu36I. Lane 7 shows a child with the mutation that encodes HbEtobicoke: the fragment of 2217 bp is cleaved into two fragments of 1388 and 829bp by Bsu36I.1% agarose gel with ethidium bromide; MM: molecular marker; bp: base pairs; NC:blank control

Mentions: Of the 14 children in this study, seven carried Hb Hasharon [alpha2 47 (CE5)Asp> His, HbA2: c.142G> C] and had co-inherited alpha-thalassemiagenes (six with genotype αα/-α3.7;Hasharon and onewith -α3.7/-α3.7;Hasharon). In the PCR-RFLP test,LIS1 fragment (2350 base pairs - bp) is cleaved into two fragments(1307 bp and 1043 bp) by the TaqI enzyme. Among the fragments generatedby the restriction enzyme, one had 894bp; this was present only in those patients whohad the mutation encoding Hb Hasharon (Figure1A-B).


Alpha chain hemoglobins with electrophoretic mobility similar to that of hemoglobin S in a newborn screening program.

Silva MR, Sendin SM, Araujo IC, Pimentel FS, Viana MB - Rev Bras Hematol Hemoter (2013)

Products of PCR and PCR-RFLP for the detection of Hb Hasharon (A & B) andEtobicoke (C)A) Products of biplex gap-PCR for four individuals. Lanes 1 to 4 show ampliconsderived from the wild HBA2 (1803 bp) and LIS genes (2351 bp).Lanes 5 to 8 amplicons from LIS and the -α3.7 hybrid gene (2033bp). Lanes 1 and 5, 2 and 6, 3 and 7, 4 and 8 derive from the same children whoseHBA2 and -α3.7 genes were amplifiedseparatelyB) Products of biplex gap-PCR, shown in Figure A, digested withaqI for the detection of the mutation that encodes HbHasharon. The fragment of 894 pb in lanes 5 and 6 indicates that these childrenhave the mutation that characterizes heterozygous Hb Hasharon in the-α3.7 hybrid geneC) Products of PCR for the HBA1 gene (2213 bp: lanes 1 and 2) andfor the HBA2 gene (2217 bp: lanes 5 and 6) derived from twodifferent individuals. Lanes 3, 4, 7 and 8 correspond to the breakdown products ofsamples 1, 2, 5 and 6, respectively, digested with the endonucleaseBsu36I. Lane 7 shows a child with the mutation that encodes HbEtobicoke: the fragment of 2217 bp is cleaved into two fragments of 1388 and 829bp by Bsu36I.1% agarose gel with ethidium bromide; MM: molecular marker; bp: base pairs; NC:blank control
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672120&req=5

f01: Products of PCR and PCR-RFLP for the detection of Hb Hasharon (A & B) andEtobicoke (C)A) Products of biplex gap-PCR for four individuals. Lanes 1 to 4 show ampliconsderived from the wild HBA2 (1803 bp) and LIS genes (2351 bp).Lanes 5 to 8 amplicons from LIS and the -α3.7 hybrid gene (2033bp). Lanes 1 and 5, 2 and 6, 3 and 7, 4 and 8 derive from the same children whoseHBA2 and -α3.7 genes were amplifiedseparatelyB) Products of biplex gap-PCR, shown in Figure A, digested withaqI for the detection of the mutation that encodes HbHasharon. The fragment of 894 pb in lanes 5 and 6 indicates that these childrenhave the mutation that characterizes heterozygous Hb Hasharon in the-α3.7 hybrid geneC) Products of PCR for the HBA1 gene (2213 bp: lanes 1 and 2) andfor the HBA2 gene (2217 bp: lanes 5 and 6) derived from twodifferent individuals. Lanes 3, 4, 7 and 8 correspond to the breakdown products ofsamples 1, 2, 5 and 6, respectively, digested with the endonucleaseBsu36I. Lane 7 shows a child with the mutation that encodes HbEtobicoke: the fragment of 2217 bp is cleaved into two fragments of 1388 and 829bp by Bsu36I.1% agarose gel with ethidium bromide; MM: molecular marker; bp: base pairs; NC:blank control
Mentions: Of the 14 children in this study, seven carried Hb Hasharon [alpha2 47 (CE5)Asp> His, HbA2: c.142G> C] and had co-inherited alpha-thalassemiagenes (six with genotype αα/-α3.7;Hasharon and onewith -α3.7/-α3.7;Hasharon). In the PCR-RFLP test,LIS1 fragment (2350 base pairs - bp) is cleaved into two fragments(1307 bp and 1043 bp) by the TaqI enzyme. Among the fragments generatedby the restriction enzyme, one had 894bp; this was present only in those patients whohad the mutation encoding Hb Hasharon (Figure1A-B).

Bottom Line: Two associations with hemoglobin S were found: one with hemoglobin Ottawa and one with hemoglobin St Luke's.Apparently these are the first cases of hemoglobin Ottawa, St Luke's, Etobicoke and the α212 gene described in Brazil.Additional tests are necessary for the correct identification of hemoglobin variants.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade Federal de Minas Gerais - UFMG, Belo Horizonte, MG, Brazil.

ABSTRACT

Objective: To characterize alpha-chain variant hemoglobins with electric mobility similar to that of hemoglobin S in a newborn screening program.

Methods: β(S) allele and alpha-thalassemia deletions were investigated in 14 children who had undefined hemoglobin at birth and an electrophoretic profile similar to that of hemoglobin S when they were six months old. Gene sequencing and restriction enzymes (DdeI, BsaJI, NlaIV, Bsu36I and TaqI) were used to identify hemoglobins. Clinical and hematological data were obtained from children who attended scheduled medical visits.

Results: THE FOLLOWING ALPHA CHAIN VARIANTS WERE FOUND: seven children with hemoglobin Hasharon [alpha2 47(CE5) Asp>His, HbA2:c.142G>C], all associated with alpha-thalassemia, five with hemoglobin Ottawa [alpha1 15(A13) Gly>Arg, HBA1:c.46G>C], one with hemoglobin St Luke's [alpha1 95(G2) Pro>Arg, HBA1:c.287C>G] and another one with hemoglobin Etobicoke [alpha212 84(F5) Ser>Arg, HBA212:c.255C>G]. Two associations with hemoglobin S were found: one with hemoglobin Ottawa and one with hemoglobin St Luke's. The mutation underlying hemoglobin Etobicoke was located in a hybrid α212 allele in one child. There was no evidence of clinically relevant hemoglobins detected in this study.

Conclusion: Apparently these are the first cases of hemoglobin Ottawa, St Luke's, Etobicoke and the α212 gene described in Brazil. The hemoglobins detected in this study may lead to false diagnosis of sickle cell trait or sickle cell disease when only isoelectric focusing is used in neonatal screening. Additional tests are necessary for the correct identification of hemoglobin variants.

No MeSH data available.


Related in: MedlinePlus