A Novel Deletion/Insertion Caused by a Replication Error in the β-Globin Gene Locus Control Region

The human β-globin enhancer LCR HS2 plays a role in forming a TAD by activating chromatin structure at neighboring CTCF sites

The human β-globin locus control region (LCR) hypersensitive site 2 (HS2) is one of enhancers for transcription of the β-like globin genes in erythroid cells. Our previous study showed that the LCR HS2 has active chromatin structure before transcriptional induction of the β-globin gene, while another enhancer LCR HS3 is activated by the induction. To compare functional difference between them, we deleted each HS (ΔHS2 and ΔHS3) from the human β-globin locus in hybrid MEL/ch11 cells. Deletion of either HS2 or HS3 dramatically diminished the β-globin transcription and disrupted locus-wide histone H3K27ac and chromatin interaction between LCR HSs and gene. Surprisingly, ΔHS2 weakened interactions between CTCF sites forming the β-globin topologically associating domain (TAD), while ΔHS3 did not. CTCF occupancy and chromatin accessibility were reduced at the CTCF sites in the ΔHS2 locus. To further characterize the HS2, we deleted the maf-recognition elements for erythroid activator NF-E2 at HS2. This deletion decreased the β-globin transcription and enhancer-promoter interaction, but did not affect interactions between CTCF sites for the TAD. In light of these results, we propose that the HS2 has a role in forming a β-globin TAD by activating neighboring CTCF sites and this role is beyond typical enhancer activity.

Alcoholic-Hepatitis, Links to Brain and Microbiome: Mechanisms, Clinical and Experimental Research

The following review article presents clinical and experimental features of alcohol-induced liver disease (ALD). Basic aspects of alcohol metabolism leading to the development of liver hepatotoxicity are discussed. ALD includes fatty liver, acute alcoholic hepatitis with or without liver failure, alcoholic steatohepatitis (ASH) leading to fibrosis and cirrhosis, and hepatocellular cancer (HCC). ALD is fully attributable to alcohol consumption. However, only 10-20% of heavy drinkers (persons consuming more than 40 g of ethanol/day) develop clinical ALD. Moreover, there is a link between behaviour and environmental factors that determine the amount of alcohol misuse and their liver disease. The range of clinical presentation varies from reversible alcoholic hepatic steatosis to cirrhosis, hepatic failure, and hepatocellular carcinoma. We aimed to (1) describe the clinico-pathology of ALD, (2) examine the role of immune responses in the development of alcoholic hepatitis (ASH), (3) propose diagnostic markers of ASH, (4) analyze the experimental models of ALD, (5) study the role of alcohol in changing the microbiota, and (6) articulate how findings in the liver and/or intestine influence the brain (and/or vice versa) on ASH; (7) identify pathways in alcohol-induced organ damage and (8) to target new innovative experimental concepts modeling the experimental approaches. The present review includes evidence recognizing the key toxic role of alcohol in ALD severity. Cytochrome p450 CYP2E1 activation may change the severity of ASH. The microbiota is a key element in immune responses, being an inducer of proinflammatory T helper 17 cells and regulatory T cells in the intestine. Alcohol consumption changes the intestinal microbiota and influences liver steatosis and liver inflammation. Knowing how to exploit the microbiome to modulate the immune system might lead to a new form of personalized medicine in ALF and ASH.

Identification and molecular characterization of a novel 163 kb deletion: The Italian (ϵγδβ)(0)-thalassemia

OBJECTIVE AND IMPORTANCE

To verify the presence of β-thalassemia in subjects showing hematologic phenotype of α-thalassemia, conduct normal molecular sequence analysis of the α-globin genes, and detect the absence of the most frequent α-thalassemia deletions.

CLINICAL PRESENTATION

A patient from Apulia (Southern Italy) was referred to our institution for the occasional founding of hypochromic polyglobulia and microcytic red blood cells associated with normal levels of Hb A2 and Hb F and normal iron parameters.

INTERVENTION AND TECHNIQUE

The patient has been investigated using Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA), quantitative real-time PCR, restriction analysis, and gap-PCR. A novel deletion, the Italian (ϵγδβ)(0)-thalassemia, has been identified. The 5' breakpoint was within a LINE element of 80 kb 3' of the ε-globin gene, and the 3' breakpoint was within a 160-bp palindrome of about 30 kb 5' of the β-globin gene. The breakpoint region was characterized by the presence of a microhomology (5'-TCT-3') and of an insertion of 43 bp owing to the duplication of the 160-bp palindrome. Comparison of the Hb and Hb A2 values of (ϵγδβ)(0)-thalassemia from the literature with those of (molecularly known) thalassemia carriers indicated a higher level of Hb A2 with respect to α-thalassemia and a lower level of Hb with respect to β(0)-thalassemia carriers.

CONCLUSION

In this study, we report the first (ϵγδβ)(0)-thalassemia case identified in Italy. To avoid misdiagnosis of β-thalassemia, we suggest verifying the presence of large deletions of the β-globin gene cluster in subjects showing a higher border line level of Hb A2 and a lower level of Hb.

Diagnosis and prevention of thalassemia

Thalassemia is the most common monogenic inherited disease worldwide and it affects most countries to various extents. This review summarizes the current approaches to phenotypic and genotypic diagnosis of thalassemia in clinical practice. Prevention strategies that encompass carrier screening, genetic counseling and prenatal diagnosis are discussed. The importance of public education and an awareness of a changing perception regarding this group of diseases are emphasized. It also addresses the impact of the rapidly increasing knowledge in disease severity modification by hemoglobin F (Hb F).

A novel 506kb deletion causing εγδβ thalassemia

We describe a novel deletion causing εγδβ thalassemia in a Pakistani family. The Pakistani deletion is 506kb in length, and the second largest εγδβ thalassemia deletion reported to date. It removes the entire β globin gene (HBB) cluster, extending from 431kb upstream to 75kb downstream of the ε globin gene (HBE). The breakpoint junction occurred within a 160bp palindrome embedded in LINE/LTR repeats, and contained a short (9bp) region of direct homology which may have contributed to the recombination event. Characterization of the deletion breakpoints has been particularly challenging due to the complexity of DNA deletion, insertion and inversion, involving a multitude of methodologies, mirroring the changing DNA analysis technologies.