Hemoglobin
Hemoglobin is a crucial protein found in red blood cells that plays a central role in transporting oxygen throughout the body. Its is a fundamental diagnostic tool in healthcare. Among its various forms, glycated hemoglobin, commonly known as HbA1c, is particularly significant as it offers a window into an individual’s average blood glucose levels over an extended period.
Biological Basis
Section titled “Biological Basis”Hemoglobin is a complex protein composed of four protein subunits, each containing a heme group capable of binding to iron. This iron-heme complex is responsible for reversibly binding oxygen in the lungs and releasing it in the tissues. Glycated hemoglobin forms when glucose molecules in the bloodstream chemically bond to hemoglobin. This non-enzymatic attachment, called glycation, is irreversible and occurs over the lifespan of red blood cells, which is typically about 2 to 3 months. Consequently, the level of glycated hemoglobin reflects the average blood glucose concentration over the preceding two to three months; higher blood glucose leads to a greater proportion of glycated hemoglobin.
Clinical Relevance
Section titled “Clinical Relevance”The of glycated hemoglobin is a cornerstone in the diagnosis and management of diabetes mellitus. It provides an objective assessment of long-term blood sugar control, helping clinicians evaluate the effectiveness of treatment strategies and identify individuals at risk for diabetes-related complications. Elevated glycated hemoglobin levels indicate sustained high blood glucose, which can lead to various health issues. Recent research has also explored the genetic factors that influence glycated hemoglobin levels, even in individuals without diabetes, indicating that genetics can contribute to baseline variations .
Another statistical consideration is that the association of individual SNPs, rs2305198 and rs7072268 , with glycated hemoglobin became statistically significant only when both were analyzed together in a multiple regression model, rather than separately. This indicates that the individual genetic contributions of these SNPs might be modest, or that their combined effect is necessary to reach statistical significance, implying a more complex genetic architecture than simple additive effects of single loci. The study also assumed an additive genetic model for these SNPs, which might not fully capture other potential genetic mechanisms, such as dominant, recessive, or epistatic interactions, that could also influence hemoglobin levels.
Population Specificity and Phenotypic Scope
Section titled “Population Specificity and Phenotypic Scope”The primary discovery cohort, the Women’s Genome Health Study, consisted exclusively of women, thereby introducing a potential cohort bias that impacts the direct generalizability of these findings to the broader population, particularly men. Although a replication sample included both sexes, the male cohort size was relatively small (N=204), which makes it challenging to fully assess sex-specific genetic effects or interactions across diverse populations with high statistical power. The precise ancestral composition of all study participants is not detailed in the available information, which means the generalizability of these genetic associations to populations of different ancestries remains to be fully explored, as genetic variants and their effects can vary significantly across ethnic groups.
Moreover, the research specifically focused on glycated hemoglobin within a non-diabetic population. While this provides valuable insights into the genetic determinants of hemoglobin levels in healthy individuals, it limits the direct applicability of these findings to individuals with diabetes or other conditions that significantly affect glucose metabolism and red blood cell lifespan. The studies do not elaborate on the specific methodologies used for glycated hemoglobin, and potential variability in or other phenotypic nuances could influence the observed effect sizes and their interpretation.
Unaccounted Confounders and Remaining Knowledge Gaps
Section titled “Unaccounted Confounders and Remaining Knowledge Gaps”While the study accounted for several important covariates such as age, sex, menopause, and BMI in its regression models, it is possible that other environmental or lifestyle factors, or gene-environment interactions, could confound or modify the observed genetic associations with glycated hemoglobin. Factors like diet, physical activity, smoking, or specific health conditions not included as covariates could play a significant role in influencing hemoglobin levels and their genetic underpinnings. The relatively small effect sizes observed for the identified SNPs suggest that these variants explain only a minor fraction of the overall variability in glycated hemoglobin, pointing towards the concept of “missing heritability.”
This “missing heritability” implies that a substantial portion of the genetic contribution to hemoglobin levels remains unexplained, likely due to a combination of many other common variants with even smaller effects, rare variants, structural variations, or complex epistatic interactions not fully captured by the current study design. Consequently, significant knowledge gaps persist regarding the full spectrum of genetic and environmental factors that comprehensively determine glycated hemoglobin levels. Future research incorporating broader sets of genetic markers, environmental exposures, and diverse populations will be crucial to fully elucidate the complex etiology of this important clinical biomarker.
Definition and Core Terminology of Hemoglobin
Section titled “Definition and Core Terminology of Hemoglobin”Hemoglobin (Hgb) is precisely defined as a fundamental “hematological phenotype”.[1]representing a critical component within the broader spectrum of blood characteristics. The term “hemoglobin” itself, often abbreviated as Hgb, refers to the metalloprotein in red blood cells that is responsible for oxygen transport. In research contexts, such as genome-wide association studies (GWAS) and linkage analyses, hemoglobin is treated as a measurable trait, providing an operational definition for its quantitative assessment.[1]Its accurate is essential for diagnosing various conditions and understanding overall hematological health.
Associated Hematological Parameters and Context
Section titled “Associated Hematological Parameters and Context”The assessment of hemoglobin levels is often conducted in conjunction with other related hematological parameters that collectively provide a comprehensive profile of red blood cell status. These include hematocrit (HCT), which measures the proportion of red blood cells in the blood; red blood cell count (RBCC); mean corpuscular volume (MCV), indicating the average size of red blood cells; and mean corpuscular hemoglobin (MCH), which reflects the average amount of hemoglobin in a red blood cell.[1]These interconnected measurements allow for a more nuanced classification of blood disorders and are crucial for establishing diagnostic criteria and research thresholds. In large-scale genetic studies, the “hemoglobin ” serves as a key quantitative trait for identifying genetic loci associated with hematological phenotypes.[1]
Genetic Classification of Hemoglobin Subtypes
Section titled “Genetic Classification of Hemoglobin Subtypes”Hemoglobin is not a singular entity but rather a family of proteins whose composition is determined by specific globin gene expression, forming a basis for its genetic classification. Different types of globin chains, encoded by distinct genes, combine to form various functional hemoglobin molecules. Key gene symbols identified includeHBA1 and HBA2 for alpha globin chains, HBB for beta globin, HBD for delta globin, HBE1 for epsilon globin, HBG1 and HBG2 for gamma globin, and HBM for mu globin.[1]The specific combination of these globin chains defines the major hemoglobin subtypes, such as adult hemoglobin (HbA), fetal hemoglobin (HbF), and minor adult hemoglobin (HbA2), reflecting a complex nosological system based on genetic architecture.
Diagnosis
Section titled “Diagnosis”Accurate diagnosis of conditions affecting hemoglobin involves a comprehensive approach, integrating routine laboratory assessments with advanced genetic and molecular analyses. The goal is to precisely identify variations in hemoglobin levels, understand their underlying causes, and distinguish them from similar conditions.
Laboratory and Biomarker Assessment
Section titled “Laboratory and Biomarker Assessment”The initial and most fundamental step in evaluating hemoglobin status involves quantitative laboratory measurements. Direct of hemoglobin (Hgb) concentration is a primary indicator of the blood’s oxygen-carrying capacity. This is typically performed as part of a complete blood count (CBC), which also includes other critical hematological phenotypes such as hematocrit (HCT), red blood cell count (RBCC), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH).[1]Deviations from established reference ranges for these parameters are essential diagnostic criteria, indicating potential anemias, polycythemias, or other hematological disorders. The collective interpretation of these values offers insights into red blood cell size, hemoglobin content per cell, and overall red blood cell mass, guiding further investigations into the etiology of abnormal hemoglobin levels.
These biochemical assays are widely available, relatively inexpensive, and possess high sensitivity for detecting abnormalities in hemoglobin and red blood cell parameters. They serve as a crucial screening tool in general health check-ups and are indicated in patients presenting with symptoms suggestive of anemia (e.g., fatigue, pallor) or polycythemia (e.g., plethora, headache). The clinical utility extends to monitoring disease progression and response to treatment for various hematological conditions. For instance, low MCV and MCH alongside reduced hemoglobin can indicate microcytic hypochromic anemias, prompting further evaluation for iron deficiency or thalassemia.[1]
Genetic and Molecular Diagnostics
Section titled “Genetic and Molecular Diagnostics”Beyond standard blood tests, genetic and molecular diagnostic methods play an increasingly vital role in elucidating the causes of abnormal hemoglobin. Genome-wide association studies (GWAS) and linkage analyses are powerful tools used to identify genetic variants, specifically single nucleotide polymorphisms (SNPs), that are associated with variations in hemoglobin levels and other hematological phenotypes.[1]These studies can pinpoint specific genomic regions and candidate genes influencing hemoglobin synthesis and red blood cell characteristics. For example, variations within the hemoglobin gene clusters, includingHBA1, HBA2 (alpha-globin genes), HBB (beta-globin gene complex), HBD (delta-globin), HBE1 (epsilon-globin), HBG1 (gamma-globin A), and HBG2 (gamma-globin G), as well as regulatory genes like KLF1, have been found to correlate with hemoglobin levels and red blood cell indices.[1]Genetic testing for specific mutations in these genes is indicated when inherited hemoglobinopathies, such as thalassemias or sickle cell disease, are suspected, especially in cases of unexplained anemia or abnormal red blood cell indices. The accuracy of genetic testing is high, providing definitive diagnoses for inherited conditions that might otherwise be challenging to distinguish solely based on phenotypic assays. Molecular markers derived from these genetic analyses offer prognostic information and can guide personalized treatment strategies, particularly in regions with high prevalence of inherited hemoglobin disorders. These methods are crucial for understanding the genetic architecture underlying hemoglobin traits and for identifying individuals at risk for specific hematological conditions.
Clinical Context and Differential Diagnosis
Section titled “Clinical Context and Differential Diagnosis”The diagnostic process for abnormal hemoglobin levels critically integrates laboratory and genetic findings within a comprehensive clinical evaluation. While specific imaging modalities or complex functional tests are not typically primary diagnostic tools for hemoglobin itself, the context provided by a patient’s medical history, physical examination, and family history is invaluable. Clinical evaluation helps to identify potential underlying conditions contributing to abnormal hemoglobin, such as chronic diseases, nutritional deficiencies, or exposure to environmental factors. The diagnostic criteria for various anemias or polycythemias often combine specific hemoglobin thresholds with other clinical and laboratory findings.
A robust differential diagnosis is essential given that numerous conditions can manifest with altered hemoglobin levels. The combination of hemoglobin concentration with other red blood cell indices (MCV, MCH) is crucial for narrowing down the possibilities. For instance, microcytic hypochromic anemia (low MCV, MCH) can indicate iron deficiency, alpha- or beta-thalassemia, or anemia of chronic disease, each requiring different confirmatory tests. Macrocytic anemia (high MCV) can point to vitamin B12 or folate deficiency, liver disease, or myelodysplastic syndromes. Genetic insights from GWAS and targeted gene sequencing are particularly useful in distinguishing inherited hemoglobinopathies from acquired forms of anemia, thus mitigating diagnostic challenges and reducing the risk of misdiagnosis.[1] This integrated approach ensures a precise diagnosis, which is fundamental for effective patient management and treatment.
Molecular Structure and Oxygen Transport Function
Section titled “Molecular Structure and Oxygen Transport Function”Hemoglobin (Hgb) is a crucial protein primarily found within red blood cells, serving as the principal transporter of oxygen from the lungs to the body’s various tissues and carbon dioxide back to the lungs. This complex metalloprotein consists of four polypeptide chains, typically two alpha-like and two beta-like globins, each cradling a heme group. The heme group, containing a central iron atom, is the functional site where oxygen reversibly binds, enabling efficient gas exchange essential for cellular respiration and overall metabolic vitality.[1]The of hemoglobin levels reflects the blood’s oxygen-carrying capacity, providing a vital indicator of an individual’s physiological state.
Genetic Regulation of Globin Synthesis
Section titled “Genetic Regulation of Globin Synthesis”The intricate process of hemoglobin synthesis is under precise genetic control, involving multiple globin genes whose expression patterns change throughout development. Adult hemoglobin (HbA) is predominantly formed by two alpha globin chains, encoded by theHBA1 and HBA2 genes, and two beta globin chains, encoded by the HBB gene.[1] During early life stages, genes such as HBE1 (epsilon globin) during embryonic development and HBG1 (gamma A globin) and HBG2 (gamma G globin) during fetal development produce different globin variants, adapting oxygen affinity to developmental needs.[1] The transcription factor KLF1(Kruppel-like factor 1) is a key regulatory element, orchestrating the expression of these globin genes and other erythroid-specific genes, while genetic variations like single nucleotide polymorphisms (SNPs) within these gene regions can significantly influence globin production and, consequently, total hemoglobin levels.[1]
Cellular Pathways of Red Blood Cell and Hemoglobin Production
Section titled “Cellular Pathways of Red Blood Cell and Hemoglobin Production”Hemoglobin production is intrinsically linked to erythropoiesis, the highly regulated developmental process of red blood cell formation that primarily occurs in the bone marrow. This cellular function involves a series of differentiation steps, during which erythroblasts synthesize vast quantities of hemoglobin and eventually enucleate to become mature red blood cells.[1]The synthesis of heme, a critical component of hemoglobin, involves complex metabolic pathways that require adequate iron supply, with proteins likeHEBP2 (heme binding protein 2) potentially playing a role in its intracellular handling or availability.[1] These molecular and cellular pathways are tightly controlled to ensure a consistent supply of functional red blood cells, capable of efficient oxygen delivery.
Systemic Homeostasis and Pathophysiological Implications
Section titled “Systemic Homeostasis and Pathophysiological Implications”Maintaining appropriate hemoglobin levels is crucial for systemic homeostasis, as deviations can have widespread physiological consequences across various tissues and organs. Parameters such as hematocrit (HCT), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) are commonly measured alongside hemoglobin to assess the overall red blood cell mass and characteristics, providing insights into the efficiency of oxygen transport.[1]Disruptions in the homeostatic mechanisms regulating hemoglobin can stem from various pathophysiological processes, including genetic disorders affecting globin structure or synthesis (e.g., thalassemias or sickle cell disease), nutritional deficiencies (e.g., iron deficiency anemia), or chronic diseases affecting erythropoiesis.[1]The body often exhibits compensatory responses to these disruptions, such as increased erythropoietin production in response to hypoxia, aiming to restore adequate oxygen-carrying capacity.
Diagnostic Utility and Genetic Influences
Section titled “Diagnostic Utility and Genetic Influences”Hemoglobin is a fundamental hematological parameter routinely assessed in clinical practice for its broad diagnostic utility. As a key component of red blood cells responsible for oxygen transport, its levels are critical indicators of overall hematological health, with deviations often signaling underlying pathologies. Recent genome-wide association studies (GWAS) have advanced our understanding of the genetic architecture influencing hemoglobin levels, identifying multiple loci and common variants, such as those inTMPRSS6, that are associated with this phenotype.[2]These genetic insights provide a foundation for personalized medicine approaches, potentially enabling earlier identification of individuals predisposed to certain hematological conditions affecting hemoglobin, and informing more targeted diagnostic workups.
Prognostic Value and Cardiovascular Risk Stratification
Section titled “Prognostic Value and Cardiovascular Risk Stratification”The levels of hemoglobin carry significant prognostic value, serving as an indicator for various health outcomes and aiding in risk stratification. Research has demonstrated a relationship between hemoglobin and cardiovascular risk factors, even in young adults, suggesting its role as an early marker for future cardiovascular events.[3]Furthermore, related red blood cell traits, such as mean red cell volume, have been identified as correlates of blood pressure, underscoring the broader connection between erythrocyte characteristics and cardiovascular health.[4] Understanding these associations allows clinicians to identify high-risk individuals and implement early prevention strategies, potentially mitigating long-term complications and guiding treatment decisions in at-risk populations.
Associations with Systemic Conditions and Treatment Implications
Section titled “Associations with Systemic Conditions and Treatment Implications”Hemoglobin levels are intricately linked to various systemic conditions and comorbidities, extending beyond primary hematological disorders. For instance, common variants in genes likeTMPRSS6are not only associated with hemoglobin levels but also with iron status and erythrocyte volume, highlighting the genetic basis of iron metabolism that can impact hemoglobin and contribute to conditions like iron deficiency anemia.[5]The comprehensive assessment of hemoglobin, often alongside other hematological phenotypes like red blood cell count and size, provides a more complete picture of a patient’s physiological state and potential overlapping phenotypes.[6]This integrated understanding is crucial for selecting appropriate treatment strategies, monitoring disease progression, and managing complications associated with conditions that affect or are affected by hemoglobin levels.
Genetic Determinants Identified in Major Cohorts
Section titled “Genetic Determinants Identified in Major Cohorts”Population studies employing large-scale cohort designs have been instrumental in uncovering genetic factors that influence glycated hemoglobin levels within the general population. One such significant effort involved a genome-wide evaluation of 14,618 participants in the Women’s Genome Health Study (WGHS), a prominent biobank study focusing on women’s health.[7]This research identified novel associations between specific single nucleotide polymorphisms (SNPs) in theHK1 gene, namely rs2305198 and rs7072268 , and glycated hemoglobin levels in a non-diabetic cohort. The findings from these large cohorts highlight the utility of extensive population datasets for identifying genetic predispositions to variations in key metabolic markers, even in individuals without a diagnosed condition.
Epidemiological Patterns and Demographic Influences
Section titled “Epidemiological Patterns and Demographic Influences”The epidemiological investigation into glycated hemoglobin has revealed consistent genetic associations across different demographic groups. The identified associations ofrs2305198 and rs7072268 with glycated hemoglobin were not only discovered in a large cohort of women but were also successfully replicated and validated in an independent sample that included both men (N=204) and women (N=251).[7]This cross-population validation, showing no evidence of interaction with sex, suggests a broad epidemiological relevance of these genetic markers, indicating their influence on hemoglobin levels is not restricted by gender. Furthermore, the analysis controlled for demographic factors such as age, sex, menopause, and BMI, demonstrating that these genetic effects are independent contributors to glycated hemoglobin variations in non-diabetic populations.[7]
Methodological Rigor in Population-Scale Genetic Studies
Section titled “Methodological Rigor in Population-Scale Genetic Studies”Robust methodologies are crucial for establishing reliable genetic associations in population studies, particularly when examining complex traits like hemoglobin. The research utilized a genome-wide association study (GWAS) approach, analyzing SNPs within a multiple regression model that also accounted for relevant covariates.[7] The initial findings from the WGHS (N=14,618) were further strengthened by a successful replication in an independent sample, which confirmed the consistent direction of effect for both rs2305198 and rs7072268 .[7] Methodological considerations, such as ensuring SNPs were in Hardy-Weinberg equilibrium and had allelic frequencies consistent across cohorts, enhanced the generalizability of the findings, although it was noted that individual SNPs did not reach significance when analyzed separately in a linear model, emphasizing the importance of multivariable modeling for detecting these effects.[7]
Key Variants
Section titled “Key Variants”Frequently Asked Questions About Hemoglobin
Section titled “Frequently Asked Questions About Hemoglobin”These questions address the most important and specific aspects of hemoglobin based on current genetic research.
1. Why are my hemoglobin numbers different from my family’s?
Section titled “1. Why are my hemoglobin numbers different from my family’s?”Your hemoglobin levels, especially glycated hemoglobin (HbA1c), are influenced by both lifestyle and genetics. Even within families, genetic variations can lead to differences in how glucose attaches to hemoglobin or how your body processes sugar. While family history plays a role, individual genetic makeup can cause variations even among close relatives.
2. Does my diet last week affect my hemoglobin test results?
Section titled “2. Does my diet last week affect my hemoglobin test results?”No, not directly. Your glycated hemoglobin (HbA1c) test reflects your average blood glucose levels over the past two to three months, not just recent meals. This is because glucose attaches to hemoglobin irreversibly for the entire lifespan of your red blood cells. So, a single week’s diet won’t significantly alter this long-term average.
3. Can my daily activity level change my long-term hemoglobin?
Section titled “3. Can my daily activity level change my long-term hemoglobin?”Yes, absolutely. Regular physical activity is a major lifestyle factor that can significantly influence your long-term hemoglobin levels by improving blood glucose control. While genetic factors contribute to your baseline, consistent exercise can help lower your average blood sugar, thereby reducing glycated hemoglobin over time.
4. Does my age or being a woman affect my hemoglobin numbers?
Section titled “4. Does my age or being a woman affect my hemoglobin numbers?”Yes, both age and sex can influence your hemoglobin levels. Studies often account for factors like age and menopause in women because they are known to impact glycated hemoglobin concentrations. While genetics play a role, these biological differences are important clinical covariates that affect individual results.
5. Will my children inherit my tendency for higher hemoglobin?
Section titled “5. Will my children inherit my tendency for higher hemoglobin?”Yes, there’s a good chance they might inherit some genetic predispositions. Research shows that genetic factors contribute to baseline variations in glycated hemoglobin levels. While lifestyle is crucial, certain genetic variants, like those near theHK1gene, can be passed down, influencing their natural hemoglobin concentrations.
6. Does my ethnic background change my hemoglobin risk?
Section titled “6. Does my ethnic background change my hemoglobin risk?”Your ethnic background can indeed play a role. Genetic variants and their effects on hemoglobin levels can vary significantly across different ethnic groups. Initial studies primarily focused on specific populations, meaning the generalizability of these genetic associations to diverse ancestries is still being explored.
7. Is a genetic test useful to understand my hemoglobin levels?
Section titled “7. Is a genetic test useful to understand my hemoglobin levels?”A genetic test could provide some insights into your baseline risk. Understanding your genetic determinants of glycated hemoglobin can help identify if you’re at higher genetic risk, potentially guiding more personalized screening or prevention strategies. However, identified genetic variants only explain a minor fraction of the overall variability.
8. Can I lower my hemoglobin even if it’s high in my family?
Section titled “8. Can I lower my hemoglobin even if it’s high in my family?”Absolutely! While you might have a genetic predisposition for higher levels, lifestyle modifications are incredibly powerful. Things like diet, regular physical activity, and maintaining a healthy weight can significantly improve your blood glucose control and lower your glycated hemoglobin, even with a family history.
9. If I have diabetes, does my genetics still impact my hemoglobin?
Section titled “9. If I have diabetes, does my genetics still impact my hemoglobin?”Yes, genetics still play a role, but the primary focus shifts. Research on genetic determinants of hemoglobin often focuses on non-diabetic populations to understand baseline variations. However, for individuals with diabetes, while genetics contribute to susceptibility, managing your condition through medication and lifestyle is the most critical factor influencing your hemoglobin.
10. Why do some people naturally have lower hemoglobin levels?
Section titled “10. Why do some people naturally have lower hemoglobin levels?”Some people naturally have lower hemoglobin levels due to a combination of genetic and environmental factors. While lifestyle choices like diet and exercise play a big part, genetic variations can influence how efficiently their bodies process glucose or how much glucose attaches to their hemoglobin. This means some individuals have a lower baseline genetically.
This FAQ was automatically generated based on current genetic research and may be updated as new information becomes available.
Disclaimer: This information is for educational purposes only and should not be used as a substitute for professional medical advice. Always consult with a healthcare provider for personalized medical guidance.
References
Section titled “References”[1] Yang, Q et al. “Genome-wide association and linkage analyses of hemostatic factors and hematological phenotypes in the Framingham Heart Study.”BMC Med Genet, 2007.
[2] Ganesh, S. K., Zakai, N. A., van Rooij, F. J., Soranzo, N., Smith, A. V., et al. “Multiple loci influence erythrocyte phenotypes in the CHARGE Consortium.” Nat Genet, vol. 41, 2009, pp. 1191–1198.
[3] Shimakawa, T., Bild, D. E. “Relationship between hemoglobin and cardiovascular risk factors in young adults.”J Clin Epidemiol, vol. 46, 1993, pp. 1257–1266.
[4] Sharp, D. S., Curb, J. D., Schatz, I. J., Meiselman, H. J., Fisher, T. C., et al. “Mean red cell volume as a correlate of blood pressure.” Circulation, vol. 93, 1996, pp. 1677–1684.
[5] Benyamin, B., Ferreira, M. A., Willemsen, G., Gordon, S., Middelberg, R. P., et al. “Common variants in TMPRSS6 are associated with iron status and erythrocyte volume.” Nat Genet, vol. 41, 2009, pp. 1173–1175.
[6] Lin, J. P., O’Donnell, C. J., Jin, L., Fox, C., Yang, Q., et al. “Evidence for linkage of red blood cell size and count: genome-wide scans in the Framingham Heart Study.”Am J Hematol, vol. 82, 2007, pp. 605–610.
[7] Pare, G, et al. “Novel association of HK1 with glycated hemoglobin in a non-diabetic population: a genome-wide evaluation of 14,618 participants in the Women’s Genome Health Study.”PLoS Genet, vol. 5, no. 1, 2009.