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alpha-Thalassaemia in Sardinian infants
Insights
A study on Sardinian newborns found 12.9% had elevated Hemoglobin Bart's, with varying levels indicating different forms of alpha-thalassaemia. Some infants also showed co-inherited beta-thalassaemia.
Area of Science:
- Genetics
- Hematology
- Public Health
Background:
- Hemoglobin Bart's is a marker for alpha-thalassaemia, a common inherited blood disorder.
- Prevalence and clinical significance of Hemoglobin Bart's in newborns require further investigation.
Purpose of the Study:
- To determine the incidence and distribution of Hemoglobin Bart's in Sardinian newborns.
- To correlate Hemoglobin Bart's levels with red cell indices, globin chain synthesis, and clinical outcomes.
Main Methods:
- Newborn screening for Hemoglobin Bart's using high-performance liquid chromatography.
- Follow-up assessments including red cell indices, globin chain synthesis analysis, and genotype determination.
Main Results:
- Overall incidence of Hemoglobin Bart's >1% was 12.9%, with trimodal distribution (1-2%, 2-10%, ~25%).
- Higher Hemoglobin Bart's levels correlated with alpha-thalassaemia, including Hemoglobin H disease and heterozygous alpha-thalassaemia.
- Some infants with high Hemoglobin Bart's levels were double heterozygotes for alpha- and beta-thalassaemia.
Conclusions:
- Hemoglobin Bart's levels in newborns provide valuable information for diagnosing alpha-thalassaemia and identifying co-inherited disorders.
- Early identification of thalassaemia carriers and affected infants is crucial for genetic counseling and management.
Abstract:
A haemoglobin survey carried out in southern Sardinian newborn infants showed an overall incidence of 12.9% with haemoglobin Bart's of more than 1%. The distribution was trimodal: low (1 to 2%), intermediate (2 to 10%), and high (about 25%). A considerable overlap was seen between the first two groups. Both the 1 to 2% and 2 to 10% groups had thalassaemia-like red cell indices at birth. Newborn infants ascertained as having alpha-thalassaemia at follow-up did not necessarily have unbalanced alpha/non-alpha chain synthesis at birth. At follow-up examination two subjects in the 25% group had developed haemoglobin H disease, and the 2 to 10% group had thalassaemia-like red cell indices and unbalanced globin chain synthesis ratios indicative of heterozygous alpha-thalassaemia. The 1 to 2% group either had normal or slightly reduced alpha-chain synthesis ratios, indicative of the silent alpha-thalassaemia carrier state. Two subjects with 2.0% and 2.5% haemoglobin Bart's at birth had heterozygous beta-thalassaemia at follow-up. Therefore, they were double heterozygotes for alpha- and beta-thalassaemia with alpha/beta-globin chain synthesis ratios of 0.81 and 0.86. Genotype assessment in a few families showed that infants with haemoglobin Bart's levels of more than 2% may have one of the genotypes --alpha/ --alpha or -- --/alpha alpha.