α‐Thalassemia: Hb H Disease and Hb Barts Hydrops Fetalis

Chui, David H.K.

doi:10.1196/annals.1345.004

Cited by 88 publications

(61 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In a-thalassemia, screening is recommended only to detect couples at risk for hydrops fetalis syndrome because severe toxemia complications (hypertension, preeclampsia) in the mother may occur (Chui 2005). So far, screening has been mostly retrospective.…”

Section: Population Control Of Thalassemias: Programs For Preventionmentioning

confidence: 99%

The Prevention of Thalassemia

Cao

Kan

2013

Cold Spring Harbor Perspectives in Medicine

208

157

View full text Add to dashboard Cite

The thalassemias are among the most common inherited diseases worldwide, affecting individuals originating from the Mediterranean area, Middle East, Transcaucasia, Central Asia, Indian subcontinent, and Southeast Asia. As the diseases require long-term care, prevention of the homozygous state constitutes a major armament in the management. This article discusses the major prevention programs that are set up in many countries in Europe, Asia, and Australia, often drawing from the experience in Sardinia. These comprehensive programs involve carrier detections, molecular diagnostics, genetic counseling, and prenatal diagnosis. Variability of clinical severity can be attributable to interactions with a-thalassemia and mutations that increase fetal productions. Special methods taht are currently quite expensive and not widely applicable are preimplantation and preconception diagnosis. The recent successful studies of fetal DNA in maternal plasma may allow future prenatal diagnosis that is noninvasive for the fetus.

show abstract

Section: Population Control Of Thalassemias: Programs For Preventionmentioning

confidence: 99%

The Prevention of Thalassemia

Cao

Kan

2013

Cold Spring Harbor Perspectives in Medicine

208

157

View full text Add to dashboard Cite

show abstract

“…6 Early detection of this severe disorder by newborn screening leads to improvement of parental information, allows anticipatory prevention, supportive therapy and treatment in case of infectious disease. 7 The association between HbBart's at birth and a-thalassaemia genotype was described in 2006, using HPLC analysis on umbilical cord blood. 8 Based on this observation, newborn screening for HbH disease is included in neonatal screening programmes in several countries.…”

Section: Introductionmentioning

confidence: 99%

Relationship between neonatal screening results by HPLC and the number of α-thalassaemia gene mutations; consequences for the cut-off value

et al. 2011

View full text Add to dashboard Cite

Objectives To evaluate the relationship between FAST peak percentage by adapted Bio-Rad Vnbs analysis using the valley-to-valley integration and genotypes with the aim to improve differentiation between severe a-thalassaemia forms (HbH disease) and the milder disease types. Method DNA analysis for a-thalassaemia was performed on 91 dried blood spot samples presenting normal and elevated FAST peak levels, selected during three years of Dutch national newborn screening. Results Significant differences were found between samples with and without a-thalassaemia mutations, regardless of the genetic profiles. No significant difference was demonstrated between HPLC in 2a/aa and 2a/2a, between 2a/2a and --/aa and between --/aa and --/2a genotypes. Conclusion This study confirms that the percentage HbBart's, as depicted by the FAST peak, is only a relative indication for the number of a genes affected in a-thalassaemia. Based on the data obtained using the modified Bio-Rad Vnbs software, we adopted a cut-off value of 22.5% to discriminate between possible severe a-thalassaemia or HbH disease and other a-thalassaemia phenotypes. Retrospectively, if this cut-off value was utilized during this initial three-year period of neonatal screening, the positive predictive value would have been 0.030 instead of 0.014.

show abstract

“…When the level of alpha globin synthesis falls below ~70% of normal, in the foetal period, excess globin chains form Hb Bart's which can be detected on routine Hb analysis (29)(30)(31)(32)(33)(34)(35). In adult life, excess globin chains form 4 tetramers of HbH in the cell and these can be identified by staining the peripheral blood with 1% brilliant cresyl blue (BCB) (36)(37)(38), or when present in sufficient quantity by routine Hb analysis (36,39). Previously alpha thalassaemia was confirmed by globin chain biosynthesis, when the alpha/ globin chain biosynthesis ratio was reduced to less than ~0.8 (40)(41)(42)(43)(44).…”

Section: Definition/diagnostic Criteriamentioning

confidence: 99%