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Compound heterozygous β(+) β(0) mutation of HBB gene leading to β-thalassemia major in a Gujarati family - A case study.

Chaudhary S, Dhawan D, Bagali PG, S Chaudhary P, Chaudhary A, Singh S, Vudathala S - Mol Genet Metab Rep (2016)

Bottom Line: After analysis, the father was found to be heterozygous for HBBc.92G > C (Codon 30 (G > C)) mutation which is β(0) type and the mother was heterozygous for HBBc.92 + 5G > C (IVS I-5 (G > C)) mutation which is β(+) type.When amniotic fluid sample was analyzed for β-globin gene (HBB), we found the occurrence of heterozygous allelic pattern for aforesaid mutations.Prenatal diagnosis helps the parents to know the thalassemic status of the fetus and enables an early decision on the pregnancy.

View Article: PubMed Central - PubMed

Affiliation: Medical Genetics and Diagnostics Division, Xcelris Labs Ltd., Old Premchand Nagar Road, Opp. Satyagrah Chhavani, Bodakdev, Ahmedabad 380015, Gujarat, India.

ABSTRACT
β-Thalassemia is a genetic disease characterized by reduced or non-functionality of β-globin gene expression, which is caused due to a number of variations and indels (insertions and deletions). In this case study, we have reported a rare occurrence of compound heterozygosity of two different variants, namely, HBBc.92G > C and HBBc.92 + 5G > C in maternal amniotic fluid sample. Prenatal β-thalassemia mutation detection in fetal DNA was carried out using nucleotide sequencing method. After analysis, the father was found to be heterozygous for HBBc.92G > C (Codon 30 (G > C)) mutation which is β(0) type and the mother was heterozygous for HBBc.92 + 5G > C (IVS I-5 (G > C)) mutation which is β(+) type. When amniotic fluid sample was analyzed for β-globin gene (HBB), we found the occurrence of heterozygous allelic pattern for aforesaid mutations. This compound heterozygous state of fetus sample was considered as β(+)/β(0) category of β thalassemia which was clinically and genotypically interpreted as β-thalassemia major. Regular blood transfusions are required for the survival of thalassemia major patients hence prenatal diagnosis is imperative for timely patient management. Prenatal diagnosis helps the parents to know the thalassemic status of the fetus and enables an early decision on the pregnancy. In the present study, we have identified compound heterozygosity for β-thalassemia in the fetus which portrays the importance of prenatal screening.

No MeSH data available.


Related in: MedlinePlus

Pedigree chart depicting the autosomal recessive inheritance pattern of β-thalassemia traits in the family.
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f0010: Pedigree chart depicting the autosomal recessive inheritance pattern of β-thalassemia traits in the family.

Mentions: Our discussion with the clinician helped us to obtain β-thalassemia genetic results of the two daughters. Their first daughter was thalassemia major with the mutations HBBc.92G > C and HBBc.92 + 5G > C in the compound heterozygous state. This compound heterozygosity condition is similar to that of fetal DNA from current (third) pregnancy of couple. The second daughter was detected with thalassemia minor with the heterozygous HBBc.92 + 5G > C mutation. The data provided by the clinician for the first two daughters along with our findings in the present study is mentioned in Table 1. Pedigree chart was prepared to depict the autosomal recessive pattern of inheritance of β-thalassemia mutations (Fig. 2).


Compound heterozygous β(+) β(0) mutation of HBB gene leading to β-thalassemia major in a Gujarati family - A case study.

Chaudhary S, Dhawan D, Bagali PG, S Chaudhary P, Chaudhary A, Singh S, Vudathala S - Mol Genet Metab Rep (2016)

Pedigree chart depicting the autosomal recessive inheritance pattern of β-thalassemia traits in the family.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834677&req=5

f0010: Pedigree chart depicting the autosomal recessive inheritance pattern of β-thalassemia traits in the family.
Mentions: Our discussion with the clinician helped us to obtain β-thalassemia genetic results of the two daughters. Their first daughter was thalassemia major with the mutations HBBc.92G > C and HBBc.92 + 5G > C in the compound heterozygous state. This compound heterozygosity condition is similar to that of fetal DNA from current (third) pregnancy of couple. The second daughter was detected with thalassemia minor with the heterozygous HBBc.92 + 5G > C mutation. The data provided by the clinician for the first two daughters along with our findings in the present study is mentioned in Table 1. Pedigree chart was prepared to depict the autosomal recessive pattern of inheritance of β-thalassemia mutations (Fig. 2).

Bottom Line: After analysis, the father was found to be heterozygous for HBBc.92G > C (Codon 30 (G > C)) mutation which is β(0) type and the mother was heterozygous for HBBc.92 + 5G > C (IVS I-5 (G > C)) mutation which is β(+) type.When amniotic fluid sample was analyzed for β-globin gene (HBB), we found the occurrence of heterozygous allelic pattern for aforesaid mutations.Prenatal diagnosis helps the parents to know the thalassemic status of the fetus and enables an early decision on the pregnancy.

View Article: PubMed Central - PubMed

Affiliation: Medical Genetics and Diagnostics Division, Xcelris Labs Ltd., Old Premchand Nagar Road, Opp. Satyagrah Chhavani, Bodakdev, Ahmedabad 380015, Gujarat, India.

ABSTRACT
β-Thalassemia is a genetic disease characterized by reduced or non-functionality of β-globin gene expression, which is caused due to a number of variations and indels (insertions and deletions). In this case study, we have reported a rare occurrence of compound heterozygosity of two different variants, namely, HBBc.92G > C and HBBc.92 + 5G > C in maternal amniotic fluid sample. Prenatal β-thalassemia mutation detection in fetal DNA was carried out using nucleotide sequencing method. After analysis, the father was found to be heterozygous for HBBc.92G > C (Codon 30 (G > C)) mutation which is β(0) type and the mother was heterozygous for HBBc.92 + 5G > C (IVS I-5 (G > C)) mutation which is β(+) type. When amniotic fluid sample was analyzed for β-globin gene (HBB), we found the occurrence of heterozygous allelic pattern for aforesaid mutations. This compound heterozygous state of fetus sample was considered as β(+)/β(0) category of β thalassemia which was clinically and genotypically interpreted as β-thalassemia major. Regular blood transfusions are required for the survival of thalassemia major patients hence prenatal diagnosis is imperative for timely patient management. Prenatal diagnosis helps the parents to know the thalassemic status of the fetus and enables an early decision on the pregnancy. In the present study, we have identified compound heterozygosity for β-thalassemia in the fetus which portrays the importance of prenatal screening.

No MeSH data available.


Related in: MedlinePlus