<b>Human α‐Thalassemia syndromes:</b>Detection of molecular defects

Kattamis, Antonios; Camaschella, Clara; Sivera, Piera; Surrey, Saul; Fortina, Paolo

doi:10.1002/(sici)1096-8652(199610)53:2<81::aid-ajh5>3.0.co;2-#

Cited by 84 publications

(46 citation statements)

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“…The -a 3.7 deletion is known to occur at significant frequencies in Black populations (7). Since in Brazil there is an elevated degree of miscegenation, it seems that even in the nonBlack population its prevalence is also high.…”

Section: Discussionmentioning

confidence: 99%

“…The hematological alterations caused by this deletion, also known as rightward a + -thalassemia, can be very mild, if not silent (7)(8)(9). It is most prevalent in the African and Mediterranean regions.…”

Section: Introductionmentioning

confidence: 99%

“…It is most prevalent in the African and Mediterranean regions. Other relatively frequent causes of a-thalassemia are the -a 4.2 deletion (leftward a + -thalassemia) found in Asian and Mediterranean populations, the --MED and -(a) 20.5 deletions, common causes of a 0 -thalassemia in the Mediterranean region, and the --SEA deletion, found with high frequency in Southeast Asia (7). Among the most common nondeletional forms, a HphI a is a pentanucleotide deletion in the splice donor site of IVS-I which abolishes a HphI site in the a 2 gene; a NcoI a and the aa NcoI are caused by base substitutions in the translational initiation codon ATG in the a 2 or in the a 1 gene, respectively, which presumably completely abolish translation and can be recognized by the loss of the NcoI site present in the initiation codon, and a third mutation, a TSAUDI a, caused by a base substitution in the highly conserved polyadenylation signal sequence AATAAA, which must prevent endonucleolytic cleavage and poly A addition to the 3 end of mRNAs (7).…”

Section: Introductionmentioning

confidence: 99%

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High prevalence of alpha-thalassemia among individuals with microcytosis and hypochromia without anemia

Borges

Wenning

Kimura

et al. 2001

Braz J Med Biol Res

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In order to determine the contribution of a-thalassemia to microcytosis and hypochromia, 339 adult outpatients seen at Unicamp University Hospital (with the exception of the Clinical Hematology outpatient clinics), who showed normal hemoglobin (Hb) levels and reduced mean corpuscular volume and mean corpuscular hemoglobin, were analyzed. Ninety-eight were Blacks (28.9%) and 241 were Caucasians (71.1%). In all cases, Hb A 2 and F levels were either normal or low. The most common deletional and nondeletional forms of a-thalassemia [-a 3.7 , -a 4.2 , --MED , -(a) 20.5 , a HphI a, a NcoI a, aa NcoI and a TSAUDI ] were investigated by PCR and restriction enzyme analyses. A total of 169 individuals (49.9%) presented a-thalassemia: 145 (42.8%) were heterozygous for the -a 3.7 deletion (-a 3.7 /aa) and 18 (5.3%) homozygous (-a 3.7 /-a 3.7 ), 5 (1.5%) were heterozygous for the nondeletional form a HphI a (a HphI a/aa), and 1 (0.3%) was a --MED carrier (--MED /aa). Among the Blacks, 56 (57.1%) showed the -a 3.7 / aa genotype, whereas 12 (12.2%) were -a 3.7 /-a 3.7 and 1 (1.0%) was an a HphI a carrier; among the Caucasians, 89 (36.9%) were -a 3.7 /aa, 6 (2.5%) had the -a 3.7 /-a 3.7 genotype, 4 (1.7%) presented the nondeletional form (a HphI a/aa), and 1 (0.4%) was a --MED carrier. These results demonstrate that a-thalassemia, mainly through the -a 3.7 deletion, is an important cause of microcytosis and hypochromia in individuals without anemia. These data are of clinical relevance since these hematological alterations are often interpreted as indicators of iron deficiency.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High prevalence of alpha-thalassemia among individuals with microcytosis and hypochromia without anemia

Borges

Wenning

Kimura

et al. 2001

Braz J Med Biol Res

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“…This finding is not surprising as the patient was of Malaysian descent, a population group in which the deletion is found in high frequencies. [7] Double α-globin deletions in cis (α 0 ) were not encountered in black subjects in our study group. This finding is not unexpected since α 0 deletions are rare in the black population, which also explains the rarity of HbH disease in this ethnic group.…”

Section: Discussionmentioning

confidence: 62%

Alpha-thalassaemia trait as a cause of unexplained microcytosis in a South African population

et al. 2016

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“…The most common clinical form is HbH disease and the most frequently encountered genotype of Hb H disease is --/-α and rarely Hb Bart's hydrops fetalis in which all four genes are deleted. In Mediterranean region, -α 3.7 , -α 4.2 , --MED and -α 20.5 deletions are the most prevalent molecular defects [2].…”

Section: To the Editormentioning

confidence: 99%