Abstract:ABSTRACT. Fetal hemoglobin (Hb F) is characteristic of the fetal development period. However, in some genetic conditions, such as hereditary persistence of fetal hemoglobin (HPFH) and deltabeta thalassemia (δβ-thalassemia), Hb F continues to be produced in adulthood. We evaluated the frequency of two mutations of HPFH, HPFH-1 and HPFH-2 African, and two mutations in δβ-thalassemia, Sicilian and Spanish, in a Brazilian population. Peripheral blood samples were collected from adults from hospitals and blood cent… Show more
“…In HPFH-3, the deletion removes 48.5 kb of a DNA segment, starting from the 5 ′ end of the ψβ gene to a region 30 kb downstream of the β-globin gene in an L1 repetitive region. This rare genetic trait is known to result from more than 40 deletions worldwide and is characterized by normal red cell indices and is asymptomatic except for raised HbF [18,19]. In our study, among the 52 patients with raised HbF, all the 28 HPFH patients showed HPFH-3 deletion, and these patients were heterozygous.…”
We found 5/18(27.β) δβ-thalassemia cases with co-inherited alpha 3.7 deletion and 3/18 (16β) cases with IVS 1-5(G-C) mutation. Patients showed features of thalassemia intermedia phenotype among which those with co-inherited IVS 1-5(G-C) mutation showed severe phenotype as compared to those with co-inherited alpha 3.7 deletion. So, we highlight importance of genotyping of patients with δβ thalassemia or HPFH and coinheritance with inherited factors which plays crucial role in clinicopathological profile and setting up prenatal diagnostic protocol.
“…In HPFH-3, the deletion removes 48.5 kb of a DNA segment, starting from the 5 ′ end of the ψβ gene to a region 30 kb downstream of the β-globin gene in an L1 repetitive region. This rare genetic trait is known to result from more than 40 deletions worldwide and is characterized by normal red cell indices and is asymptomatic except for raised HbF [18,19]. In our study, among the 52 patients with raised HbF, all the 28 HPFH patients showed HPFH-3 deletion, and these patients were heterozygous.…”
We found 5/18(27.β) δβ-thalassemia cases with co-inherited alpha 3.7 deletion and 3/18 (16β) cases with IVS 1-5(G-C) mutation. Patients showed features of thalassemia intermedia phenotype among which those with co-inherited IVS 1-5(G-C) mutation showed severe phenotype as compared to those with co-inherited alpha 3.7 deletion. So, we highlight importance of genotyping of patients with δβ thalassemia or HPFH and coinheritance with inherited factors which plays crucial role in clinicopathological profile and setting up prenatal diagnostic protocol.
“…HPFH is associated either with the occurrence of single-point mutations in the promoter region of two γ chains or β-globin gene cluster deletions. It is usually characterised in heterozygotes by higher levels of HbF (upto 30%) with normal red cell indices [3]. Individuals with these disorders exhibit milder clinical symptoms than those with typical β-thalassemia, due to the beneficial effect of HbF on red blood cell production and survival…”
“…On the other hand, δβ‐thal Spanish is less common in Latin American countries as only few reports have been published in Venezuela (0.7%) and Brazil (present in 3/60 individuals with increased HbF); however, in Spain, this variant is rather frequent as 7% of thalassemia carriers have δβ‐thal Spanish type; therefore, we assume that this allele was introduced to Mexican population through the Spaniards during the colonization.…”
Considering the novel mutations -90C>G, -20 bp Cd78/85, IVS2:2T>G and the first observation of IVS1:6T>C, the molecular spectrum of β-thal in Mexicans comprises 21 different mutations, confirming the high allelic heterogeneity in Mexicans.
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