Hereditary Persistence Of Fetal Hemoglobin-Beta-Thalassemia Syndrome

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Retrieved

2021-01-23

Source

Orphanet

Trials

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Genes

HBB, HBG2, HBG1, KRT87P

Drugs

Allogeneic multi-virus specific T lymphocytes targeting BK virus, cytomegalovirus, human herpesvirus-6, Epstein Barr virus and adenovirus, Sevuparin, autologous CD34+ hematopoietic stem cells with a CRISPR-edited erythroid enhancer region of the BCL11A gene, haematopoietic stem cells and blood progenitors umbilical cord-derived expanded with (1R, 4R)-N1-(2-benzyl-7-(2-methyl-2H-tetrazol-5-yl)-9H-pyrimido[4,5-b]indol-4-yl)cyclohexane-1,4-diamine dihydrobromide dihydrate

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Hereditary persistence of fetal hemoglobin (HPFH) associated with beta-thalassemia (see this term) is characterized by high hemoglobin (Hb) F levels and an increased number of fetal-Hb-containing-cells.

Epidemiology

Prevalence of this form is not known.

Clinical description

The association of HPFH with beta-thalassemia mitigates the clinical manifestations which vary from a normal state to beta-thalassemia intermedia (see this term).

Etiology

HPFH is due to deletions in the beta-globin gene cluster or point mutations in the HBG1 and HBG2 genes (11p15.5).

Diagnostic methods

Diagnosis is based on the presence of a significant elevation in HbF ranging from 10-40% in heterozygotes with normal or near normal red blood cell indices. HbF is homogeneously distributed among the erythrocytes and HbA2 is normal or reduced.

Differential diagnosis

The distinction between HPFH and delta-beta-thalassemia (see this term) is subtle and should be confirmed by alpha-beta-globin chain synthesis ratio and DNA analysis since the distinction between these two conditions is not always possible from routine hematologic analyses.

Genetic counseling

HPFH transmission is co-dominant. Homozygosis for the non-deletional form has to date been reported in rare cases.