Contributions
Abstract: EP850
Type: E-Poster Presentation
Session title: Iron metabolism, deficiency and overload
Background
In Thailand, the prevalence of iron deficiency anemia (IDA) in children is around 10-16%. Common etiologies of IDA include inadequate iron intake and chronic blood loss. Other than those, mutations in TMPRSS6 gene have been reported. The TMPRSS6 gene regulates hepcidin expression by encoding Matriptase-2, an enzyme which cleaves a cofactor promoting hepcidin transcription. With mutations to such gene, the patient has an elevated hepcidin level despite the iron deficiency status and is described as having iron refractory IDA (IRIDA). Several studies show that the TMPRSS6 gene polymorphisms, for example rs855791 (p.V736A) and rs2235324 (p.K253E), associate with lower iron status. Whether these single nucleotide polymorphisms are associated with an increased risk of developing IDA in our population especially in children is an enticing question.
Aims
- To identify the prevalence of TMPRSS6 gene polymorphism (p.V736A) in the study population
- To identify the association between the TMPRSS6 polymorphism (p.V736A) and the risk of iron deficiency anemia in Thai children
Methods
A total of 415 students aged between 9-15 years, from 3 schools were all included in this study. Their blood was taken for complete blood count, iron study and hepcidin assay. Directed by the results, they were then classified into normal, iron depletion (ID) and IDA groups, according to World Health Organization’s definition. For DNA study, the DNA containing the p.V736A (c.T2321C) polymorphism was amplified by polymerase chain reaction (PCR) and identified by restriction fragment length polymorphism (RFLP) in all participants. Chi-square test was used to determine the difference in iron status with respect to genotypes (TT, CT and TT). Logistic regression analysis was used to determine its association with serum iron, ferritin and hepcidin levels.
Results
The T allele frequency in this population was 0.6. The percentage of TT genotype was highest in IDA group (48%) compared to ID (36.6%) and normal group (31.9%) although there were no significant differences, p-value= 0.226. The TT genotype had significantly lower serum iron when compared to the CT genotype (serum iron mean difference -7.9 [SE 3.2] mmol/L, p-value = 0.043 whereas it was not significant when compared to the CC genotype (mean difference -7.4 [SE 4.8] mmol/L, p-value = 0.354). There were also no significant differences of hepcidin and ferritin levels among genotypes.
Conclusion
The TT polymorphism of c.T2321C is common among Thai children with IDA and associates with a lower level of serum iron when compared to the other genotypes. Other polymorphisms of the TMPRSS6 gene will be further studied to determine additional effects of combined polymorphisms to the iron status.
Keyword(s): Gene polymorphism, Iron deficiency anemia
Abstract: EP850
Type: E-Poster Presentation
Session title: Iron metabolism, deficiency and overload
Background
In Thailand, the prevalence of iron deficiency anemia (IDA) in children is around 10-16%. Common etiologies of IDA include inadequate iron intake and chronic blood loss. Other than those, mutations in TMPRSS6 gene have been reported. The TMPRSS6 gene regulates hepcidin expression by encoding Matriptase-2, an enzyme which cleaves a cofactor promoting hepcidin transcription. With mutations to such gene, the patient has an elevated hepcidin level despite the iron deficiency status and is described as having iron refractory IDA (IRIDA). Several studies show that the TMPRSS6 gene polymorphisms, for example rs855791 (p.V736A) and rs2235324 (p.K253E), associate with lower iron status. Whether these single nucleotide polymorphisms are associated with an increased risk of developing IDA in our population especially in children is an enticing question.
Aims
- To identify the prevalence of TMPRSS6 gene polymorphism (p.V736A) in the study population
- To identify the association between the TMPRSS6 polymorphism (p.V736A) and the risk of iron deficiency anemia in Thai children
Methods
A total of 415 students aged between 9-15 years, from 3 schools were all included in this study. Their blood was taken for complete blood count, iron study and hepcidin assay. Directed by the results, they were then classified into normal, iron depletion (ID) and IDA groups, according to World Health Organization’s definition. For DNA study, the DNA containing the p.V736A (c.T2321C) polymorphism was amplified by polymerase chain reaction (PCR) and identified by restriction fragment length polymorphism (RFLP) in all participants. Chi-square test was used to determine the difference in iron status with respect to genotypes (TT, CT and TT). Logistic regression analysis was used to determine its association with serum iron, ferritin and hepcidin levels.
Results
The T allele frequency in this population was 0.6. The percentage of TT genotype was highest in IDA group (48%) compared to ID (36.6%) and normal group (31.9%) although there were no significant differences, p-value= 0.226. The TT genotype had significantly lower serum iron when compared to the CT genotype (serum iron mean difference -7.9 [SE 3.2] mmol/L, p-value = 0.043 whereas it was not significant when compared to the CC genotype (mean difference -7.4 [SE 4.8] mmol/L, p-value = 0.354). There were also no significant differences of hepcidin and ferritin levels among genotypes.
Conclusion
The TT polymorphism of c.T2321C is common among Thai children with IDA and associates with a lower level of serum iron when compared to the other genotypes. Other polymorphisms of the TMPRSS6 gene will be further studied to determine additional effects of combined polymorphisms to the iron status.
Keyword(s): Gene polymorphism, Iron deficiency anemia