Sickle liver disease--an unusual presentation in a compound heterozygote for HbS and a novel beta-thalassemia mutation

Global distribution of β-thalassemia mutations: An update

One excellent illustration of how a single gene abnormality may result in a spectrum of disease incidence is the incredible phenotypic variety of β-thalassemia, which spans from severe anemia and transfusion needs to an utterly asymptomatic sickness. However, genetic causes of β-thalassemia and how the anemia's severity might be altered at various stages in its pathophysiology have been well investigated. There are currently known to be more than 350 mutations that cause genetic disease. However only 20 β thalassemia mutations account for more than 80% of the β thalassemia mutation across the globe due to phenomenon of geographical clustering where each population has a few common mutations together with a varying number of rare ones. Due to migration of the population, the spectrum of thalassemia mutation in changing from time to time. In this review, efforts are made to collate β globin gene mutations in different countries and populations.

Molecular Mechanisms of Hepatic Dysfunction in Sickle Cell Disease: Lessons From The Townes Mouse Model

Sickle cell disease (SCD) is an autosomal-recessive-genetic disorder that affects ~100,000 Americans and millions of people worldwide. Erythrocyte sickling, vaso-occlusion, sterile inflammation and hemolysis are the major pathophysiological pathways leading to liver injury in SCD. Although hepatic dysfunction affects up to 10-40% of SCD patients, therapeutic approaches to prevent liver injury in SCD are not known, and the molecular mechanisms promoting progressive liver injury in SCD remain poorly understood. Animal models have been beneficial in bridging the gap between preclinical and translational research in SCD. Recent advances in methodology have allowed the development of several humanized mouse models to address various aspects of SCD related liver diseases. This review provides an overview of current knowledge of the molecular mechanisms and potential therapeutic options of SCD associated liver dysfunction using the Townes mouse model.

The Liver in Sickle Cell Disease

Patients with sickle cell disease can develop liver disease as a result of intrahepatic sickling of erythrocytes, viral hepatitis and iron overload secondary to multiple blood transfusions, and gallstone disease as a result of chronic hemolysis. The spectrum of clinical liver disease is wide and often multifactorial. Some patients develop cirrhosis that may progress to end-stage liver failure. Limited evidence exists for medical treatments. Exchange blood transfusions may improve outcomes in the acute liver syndromes. Liver transplantation may be an option for chronic liver disease. The role for prophylactic cholecystectomy in preventing complications of gallstone disease is controversial.

Mild β(+)-thalassemia associated with two linked sequence variants: IVS-II-839 (T>C) and IVS-II-844 (C>A)

We report four unrelated families with a mild β(+)-thalassemia (β(+)-thal) allele consisting of two sequence variants at the 3' end of IVS-II: IVS-II-839 (T>C) (HBB: c.316-12T>C) and IVS-II-844 (C>A) (HBB: c.316-7C>A). These sequence variants alter the conserved polypyrimidine tract of the consensus splice acceptor sequence (Y11NYAG/G), which could reduce splicing efficiency. This may represent a common, yet under-diagnosed β(+)-thal allele in African populations.

Liver Cirrhosis in a Patient with Sickle Cell Trait (Hb Sβ Thalassemia) without Other Known Causes of Hepatic Disease

Liver involvement in patients with sickle cell anemia/trait includes a wide range of alterations, from mild liver function test abnormalities to cirrhosis and acute liver failure. Approximately 15–30% of patients with sickle cell anemia present cirrhosis at autopsy. The pathogenesis of cirrhosis is usually related to chronic hepatitis B or C infection or to iron overload resulting from the many transfusions received by these patients in their lifetime. Thus, cirrhosis has been described almost exclusively in patients with sickle cell anemia, while only mild liver abnormalities have been associated with the sickle cell trait. In the present case study, we describe a young Mediterranean man carrying a sickle cell trait (Hb Sβ⁺ thalassemia) who developed liver cirrhosis being negative for hepatitis C and B viruses or for other causes of cirrhosis and not receiving chronic blood transfusions.