Hemoglobin Mizuho or Beta 68 (E 12) Leucine → Proline, a new Ufistarle Variaiit Associated with Severe Hemolytic Anemia

Ohba, Yusuke; Miyaji, T; Matsuoka, M; Sugiyama, Kohachiro; Suzuki, Takashi; Sugiura, T.

doi:10.3109/03630267709027864

Cited by 62 publications

(9 citation statements)

References 9 publications

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“…Hb Mizuho is very rare. To our knowledge, only 6 cases have been reported in the literature [ 1 – 6 ], with only one adult patient. Hb Mizuho was first reported in a Japanese girl (1), next in an Italian girl (2), and later in boys from USA (3) and the Netherlands (4).…”

Section: Discussionmentioning

confidence: 99%

The rare hemoglobin variant Hb Mizuho: report of a Swiss family and literature review

et al. 2021

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Hb Mizuho is a very rare unstable hemoglobin; here, we describe the clinical history of three Swiss family members with Hb Mizuho together with a systematic review of the previously six published cases. The clinical history of the adult woman we report here is unique since this is the first Hb Mizuho presenting with Moyamoya complications and the first case reported with long-term erythrocyte exchange. The literature review showed that Hb Mizuho was mainly reported as a de novo mutation, with the exception of children descended from known cases. All published patients with this unstable hemoglobin showed severe hemolytic anemia with the exception of one; all were regularly transfused. Patients with higher HbF levels might require fewer transfusions. All patients underwent splenectomy at a median age of 4 years and had variable clinical improvement; some achieved complete resolution of transfusion dependency after splenectomy. Iron overload in Hb Mizuho patients seems to be mainly attributed to transfusions and has less to do with ineffective erythropoiesis. Diagnosis might be challenging; a normal hemoglobin electrophoresis should not rule out the diagnosis of unstable hemoglobin in patients with otherwise unexplained hemolytic anemia. This series shows the enormous utility of using molecular techniques for diagnosis.

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Section: Discussionmentioning

confidence: 99%

The rare hemoglobin variant Hb Mizuho: report of a Swiss family and literature review

et al. 2021

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“…Hb Mizuho is a severely unstable Hb variant. It has been found four times in patients who presented with severe hemolytic anemia, and all instances were believed to be de novo mutations [13][14][15]. The instability of this variant is due to the introduction of a proline residue in helix E, which disrupts the alpha helix and decreases its ability to bind the heme group.…”

Section: Discussionmentioning

confidence: 99%

“…The adjacent valine (E11) is a heme binding site, so mutations at this site might be expected to result in altered oxygen affinity. Three different mutations have been described at b68: Hb Mizuho (b68 Leu?Pro) [13][14][15], Hb Brisbane (also known as Hb Great Lakes) (b68 Leu?Phe) [16][17][18], and Hb Loves Park. Hb Jamaica Plain [4] is a doubly substituted variant that contains the Hb Loves Park substitution.…”

Section: Discussionmentioning

confidence: 99%

Hemoglobin Loves Park [β68 (E12) Leu→Phe]: Report of five cases including one originating from a de novo mutation

et al. 2006

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Hemoglobin (Hb) Loves Park [b68 (E12) Leu?Phe] was identified in a 2-year-old Portuguese boy with anemia, microcytosis, and hypochromia. This Hb variant was detected by isoelectric focusing and quantified by reverse-phase high-performance liquid chromatography (HPLC) (48.4%), and the DNA mutation was identified by HBB (b-globin gene) sequencing. Hematological and biochemical analyses performed on his parents revealed normal hematological parameters and normal hemoglobin and globin chain profiles. DNA sequence analysis of the HBB gene of both parents showed the absence of the Hb Loves Park mutation. Study of the haplotypes in the b-globin gene cluster confirmed parenthood. Moreover, paternity was confirmed by the study of nine short tandem repeats (STRs) and four variable-number tandem repeat (VNTRs) loci. The most likely explanation for these results is that the Hb Loves Park mutation has occurred de novo in this family. The original American cases of Hb Loves Park, from a family of Italian origin, which were never published, as well as two additional cases, are also included in this report. Functional studies revealed that Hb Loves Park is stable and has a decreased oxygen affinity. Am. J. Hematol. 81:256-261, 2006. V V C 2006 Wiley-Liss, Inc.

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“…Hemoglobin electrophoresis revealed elevation of HbF of 12% with normal amounts of Hbs A and A 2 (83% and 3%, respectively). β-globin gene sequencing revealed heterozygous Hb Mizuho (βLeu68Pro) [9]. …”

Section: Case Reportsmentioning

confidence: 99%

The diagnostic dilemma of congenital unstable hemoglobinopathies

Yates

Mortier

Hyde

et al. 2010

Pediatric Blood & Cancer

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Unstable hemoglobin variants represent a rare etiology of congenital hemolytic anemia. Without a high index of suspicion, plus proper laboratory testing and interpretation, the correct diagnosis can be elusive. We report on 5 children who were initially thought to have other congenital disorders such as hereditary spherocytosis or thalassemia, before β-globin gene sequencing led to the definitive diagnosis. Recognizing the variable clinical presentation and laboratory data reported will aid clinicians in diagnosis of unstable hemoglobins variants in children with atypical forms of hemolytic anemia, particularly those with low pulse oximetry values or whose hemoglobin electrophoresis suggest β –thalassemia trait.

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Hemoglobin Mizuho or Beta 68 (E 12) Leucine → Proline, a new Ufistarle Variaiit Associated with Severe Hemolytic Anemia

Cited by 62 publications

References 9 publications

The rare hemoglobin variant Hb Mizuho: report of a Swiss family and literature review

The rare hemoglobin variant Hb Mizuho: report of a Swiss family and literature review

Hemoglobin Loves Park [β68 (E12) Leu→Phe]: Report of five cases including one originating from a de novo mutation

The diagnostic dilemma of congenital unstable hemoglobinopathies

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