Heterogeneity of Hemoglobin H Disease in Childhood

Abstract

HCS should be recognized as a distinct thalassemia syndrome with a high risk of life-threatening anemia during febrile illnesses. HbH was not associated with an increased rate of severe anemia with infections and was managed without blood transfusions. Many patients with these disorders had mixed ethnic backgrounds, which highlights the need for extended newborn screening in populations that are traditionally considered to be at low risk for hemoglobin H disease.

Non-transfusion-dependent thalassemias

“…20,21 In addition to deletional forms, there are at least 70 forms of non-deletional hemoglobin H disease which are typically associated with a more severe phenotype, the most commonly described non-deletional hemoglobin H disease forms are hemoglobin H Constant Spring but also including hemoglobin H Paksé, Quong Sze, and Suan Dok. [22][23][24][25] These deletional and non-deletional hemoglobin H diseases are the NTDT forms covered in this review. It should be noted that the most severe forms of non-deletional hemoglobin H disease may become completely transfusion-dependent (hemoglobin H hydrops) in which case they are considered similar to {β}-thalassemia major patients.…”

“…42 Nonetheless, iron overload in NTDT patients is a cumulative process as evident from studies documenting positive correlations between iron overload indices and advancing age. 25,41,[43][44][45] Thus, a considerable proportion of NTDT patients eventually accumulate iron to liver iron concentration thresholds of clinical significance. 25,40,42,46,47 An association between iron loading evident from longitudinal elevations in serum ferritin level and worsening of hepatic fibrosis in patients with β-thalassemia intermedia has been established.…”

“…25,41,[43][44][45] Thus, a considerable proportion of NTDT patients eventually accumulate iron to liver iron concentration thresholds of clinical significance. 25,40,42,46,47 An association between iron loading evident from longitudinal elevations in serum ferritin level and worsening of hepatic fibrosis in patients with β-thalassemia intermedia has been established. 48 Several case reports and case series also suggest an association between iron overload and hepatocellular carcinoma in this patient population.…”

Hemoglobin Variants: Biochemical Properties and Clinical Correlates

“…This is due to the cytotoxic effects of the unstable Constant Spring protein. Although most common in Southeast Asia, Hb Constant Spring is increasingly identified in other geographic regions, largely through global migration (Lal et al 2011). In fact, it was first discovered in a Chinese family living in Constant Spring, Jamaica.…”

The Genotypes of α-Thalassemia and Genotypes Frequencies of α-Thalassemia in Hatay

“…α1 geni (HBA1) α2 genine göre (HBA2) iki-üç kat daha az globin zinciri üretir ve bu yüzden HBA2 geninde oluşan delesyonlar neticesinde klinik tablo daha belirgin olur. Genlerde, regülatör olarak görev yapan HS40 bölgesinde oluşan delesyonlar, α-globin zincir üretimini bozar (5 Çalışmamızda, α-talasemi α2 IVS-5nt sadece 1 (%0.25) hastada görülmektedir. Ankara için bu oran %8, Adana için %4.6, Isparta için ise %5.55 olarak bildirilmiştir (9,(11)(12).…”