Hyperbilirubinemia and cholelithiasis in Chinese patients with hemoglobin H disease

Αlpha-thalassemia: A practical overview

α-Thalassemia is an inherited blood disorder characterized by decreased synthesis of α-globin chains that results in an imbalance of α and β globin and thus varying degrees of ineffective erythropoiesis, decreased red blood cell (RBC) survival, chronic hemolytic anemia, and subsequent comorbidities. Clinical presentation varies depending on the genotype, ranging from a silent or mild carrier state to severe, transfusion-dependent or lethal disease. Management of patients with α-thalassemia is primarily supportive, addressing either symptoms (eg, RBC transfusions for anemia), complications of the disease, or its transfusion-dependence (eg, chelation therapy for iron overload). Several novel therapies are also in development, including curative gene manipulation techniques and disease modifying agents that target ineffective erythropoiesis and chronic hemolytic anemia. This review of α-thalassemia and its various manifestations provides practical information for clinicians who practice beyond those regions where it is found with high frequency.

Mechanisms Underlying the Prevention and Treatment of Cholelithiasis Using Traditional Chinese Medicine

Cholelithiasis is a major public health concern that necessitates highly effective, feasible, and recurrence-preventing therapies. Currently available surgical treatments and medications cannot effectively avoid the recurrence of cholelithiasis. Hence, several Chinese herbal compounds (CHCs) are considered for the treatment of cholelithiasis, considering that they can effectively discharge gallstones and prevent the recurrence of such condition. In the present narrative review, we aim to summarize the underlying mechanisms of currently used CHCs in the treatment of cholelithiasis and to describe the current situation of traditional Chinese medicine (TCM) use for cholelithiasis. Several commonly used CHCs were used to illustrate these issues. We found that the mechanisms underlying the CHC treatments rely on the amelioration of the biliary dynamics factors, maintenance and protection of the liver function, reduction of the cholesterol and bilirubin levels, and regulation of the inflammatory reactions. CHCs as treatments based on TCM can ameliorate the overall bodily function, thereby preventing the recurrence of cholelithiasis. Appropriate application of CHCs would be beneficial for patients and clinicians, although the safety and efficacy of CHCs need further verification.

Serum Total Bilirubin, not Cholelithiasis, is Influenced by UGT1A1 Polymorphism, Alpha Thalassemia and β(s) Haplotype: First Report on Comparison between Arab-Indian and African β(s) Genes

Background

We explored the potential relationship between steady state serum bilirubin levels and the incidence of cholelithiasis in the context of UGT1A1 gene A(TA)nTAA promoter polymorphism in Omani sickle cell anemia (SCA) patients, homozygotes for African (Benin and Bantu) and Arab-Indian β^S haplotypes, but sharing the same microgeographical environment and comparable life style factors.

Methods

136 SCA patients were retrospectively studied in whom imaging data including abdominal CT scan, MRI or Ultrasonography were routinely available. Available data on the mean steady state hematological/biochemical parameters (n=136), β^s haplotypes(n=136), α globin gene status (n=105) and UGT1A1 genotypes (n=133) were reviewed from the respective medical records.

Results

The mean serum total bilirubin level was significantly higher in the homozygous UGT1A1(AT)₇ group as compared to UGT1A1(AT)₆ group. Thus, not cholelithiasis but total serum bilirubin was influenced by UGT1A1 polymorphism in this SCA cohort.

Conclusion

As observed in other population groups, the UGT1A1 (AT)₇ homozygosity was significantly associated with raised serum total bilirubin level, but the prevalence of gallstones in the Omani SCA patients was not associated with α thalassaemia, UGT1A1 polymorphism, or β^s haplotypes.

Implementation of newborn screening for hemoglobin h disease in mainland china

Hemoglobin H disease is the most severe non-fatal form of α-thalassemia syndrome characterized by pronounced microcytic hypochromic hemolytic anemia. It is predominantly seen in Southeast Asia, the Middle East and the Mediterranean. Studies suggest that hemoglobin H disease is not as benign a disorder as previously thought. Newborn screening for hemoglobin H disease is especially appealing because the screening test is based on the detection of hemoglobin Bart's (γ4) that is only possible within the newborn period. In this study, we reported on a 4-year period of newborn screening program at a mainland Chinese hospital, which detected 35 babies with hemoglobin H disease in a total of 26 152 newborns. The overall prevalence for hemoglobin H disease among all newborns in southern China is ~1 in 1,000. These children need appropriate follow-up and potential comprehensive care during their growth and development.

A genome-wide association study of total bilirubin and cholelithiasis risk in sickle cell anemia

Serum bilirubin levels have been associated with polymorphisms in the UGT1A1 promoter in normal populations and in patients with hemolytic anemias, including sickle cell anemia. When hemolysis occurs circulating heme increases, leading to elevated bilirubin levels and an increased incidence of cholelithiasis. We performed the first genome-wide association study (GWAS) of bilirubin levels and cholelithiasis risk in a discovery cohort of 1,117 sickle cell anemia patients. We found 15 single nucleotide polymorphisms (SNPs) associated with total bilirubin levels at the genome-wide significance level (p value <5 × 10(-8)). SNPs in UGT1A1, UGT1A3, UGT1A6, UGT1A8 and UGT1A10, different isoforms within the UGT1A locus, were identified (most significant rs887829, p = 9.08 × 10(-25)). All of these associations were validated in 4 independent sets of sickle cell anemia patients. We tested the association of the 15 SNPs with cholelithiasis in the discovery cohort and found a significant association (most significant p value 1.15 × 10(-4)). These results confirm that the UGT1A region is the major regulator of bilirubin metabolism in African Americans with sickle cell anemia, similar to what is observed in other ethnicities.

Weighing the evidence for newborn screening for Hemoglobin H disease

OBJECTIVE

To conduct a systematic review to assist the United States Secretary of Health and Human Services Advisory Committee on Heritable Disorders in Newborns and Children (SACHDNC) to determine whether Hemoglobin H screening should be included among the core recommended conditions for newborn screening.

STUDY DESIGN

We identified 21 articles in MEDLINE from 1989 to March 2010 that provided evidence regarding screening, treatment, and outcomes associated with Hemoglobin H disease.

RESULTS

In California, newborn screening has identified 9 cases per 100 000 of deletional hemoglobin H disease and 0.6 cases per 100 000 of nondeletional hemoglobin H disease. Five cases of hemoglobin Bart's hydrops fetalis syndrome were also identified in over ten years of screening for Hemoglobin H disease. Although Hemoglobin H disease is associated with a wide range of morbidity, no studies were found that evaluated the benefits of early identification and treatment.

CONCLUSIONS

The SACHDNC found the data insufficient to recommend that states adopt newborn screening for Hemoglobin H disease.

Organ-specific hemosiderosis and functional correlation in Chinese patients with thalassemia intermedia and hemoglobin H disease

We performed MRI assessment in 37 adult Chinese patients with thalassemia intermedia and hemoglobin H disease. Despite abnormal ferritin and liver T2*, only 5% of patients had cardiac hemosiderosis. The two patients with reduced ejection fraction had normal cardiac T2*. Half of the cases showed pituitary and pancreatic iron loading. Subclinical endocrine abnormalities (HOMA, insulin growth factor) showed correlation with pancreatic, pituitary, and cardiac MRI values. Prospective data with serial functional and imaging monitoring is needed to verify the utility for chelation to improve cardiac and endocrine function in this group of patients.

Hb H disease: clinical course and disease modifiers

Hemoglobin H (Hb H) disease is the most common form of thalassemia intermedia and has many features that require careful consideration in management. In the majority of cases, Hb H disease results from double heterozygosity for α0-thalassemia due to deletions that remove both linked α-globin genes on chromosome 16, and deletional α+-thalassemia from single α-globin gene deletions (--/−α). However, Hb H disease may occur from interactions between α0-thalassemia with non-deletional mutations (αTα or αT) or with abnormal hemoglobins such as Hb Constant Spring, Hb Paksé, Hb Quong Sze, and Hb Pak Num Po. In a steady state, patients with Hb H diseases have hemoglobin levels around 9 to 10 g/dL; however, during hemolytic crisis, which frequently develops in or after acute infections with high fever, the hemoglobin level may drop significantly and patients can develop shock or renal shutdown. Even though splenectomy leads to significant elevation of hemoglobin levels, it is not recommended because the majority of patients do well with said steady-state hemoglobin levels. Patients with non-deletional Hb H disease are usually more anemic with significant splenomegaly, and some may require regular blood transfusions and be even as severe as “Hb H hydrops fetalis.” However, there is no clear genotype-phenotype correlation associated with this severe clinical syndrome since patients with identical genotypes do not necessary show the same severity. This suggests that other genetic and environmental factors play a role in modifying the degree of clinical severity in patients with non-deletional Hb H disease.

Gallstone disease: from genes to evidence-based therapy

The number of gallstone patients is increasing in ageing populations with a high prevalence of metabolic syndrome and obesity. Recently variants of hepatic ATP binding cassette transporters have been identified as genetic susceptibility factors for gallstone disease, pointing to novel means for risk assessment and prevention. Although laparoscopic cholecystectomy is the mainstay of therapy for symptomatic gallbladder stones, the clinical management of gallstone disease is changing rapidly, with an increase in day case surgery and the advent of transluminal endoscopic surgery. Here, we summarize the molecular and genetic mechanisms of gallstone formation as well as the current evidence-based algorithms for diagnosis and therapy of gallbladder and bile duct stones.

Genetics of biliary tract diseases: new insights into gallstone disease and biliary tract cancers

PURPOSE OF REVIEW

Chronic biliary diseases are due to complex interactions between environmental and genetic factors. Here we summarize the current knowledge of genetic factors that contribute to common biliary diseases, focusing on gallstones and carcinogenesis, and review the recent association studies.

RECENT FINDINGS

Since most studies were based on small sample sizes, replication of the findings is mandatory. Recently a large twin study confirmed a genetic predisposition to gallstones and a genome-wide association scan identified the hepatocanalicular cholesterol transporter ABCG8 as the common susceptibility factor for gallstone disease. Genetic studies in patients with cholangiocarcinoma indicate that genes controlling the metabolism and transport of xenobiotics or modulating chronic inflammation may determine individual susceptibility.

SUMMARY

Genetic studies have identified the first susceptibility factors for gallstones and biliary tract cancers, but most results have yet to be replicated. In the future, genome-wide studies in different populations are likely to identify the entire set of genes contributing to chronic biliary diseases. Since the disease phenotypes result from the manifestation of susceptibility factors under the influence of environmental triggers, the discovery of these genes will open avenues to control environmental challenges and lead to novel strategies for risk assessment ('gene signatures') and prevention.