Coinheritance of Hb D-Punjab and β-thalassemia: diagnosis and implications in prenatal diagnosis

β0-Thalassemia Caused by a Novel Nonsense Mutation [c.199A > T]

We report two hemoglobinopathy cases involving a novel β-thalassemia (β-thal) nonsense mutation, HBB:c.199A > T. One patient had Hb S/β-thal, and a second unrelated patient had Hb D-Punjab/β-thal. The HBB:c.199A > T mutation introduces a premature termination codon at amino acid codon 66 (AAA→TAA) in exon 2, resulting in typical high Hb A2 β0-thal.

Profile of Hemoglobin D (HbD) Disease in Eastern Uttar Pradesh: A Single-Center Experience

Hemoglobin D (HbD) disease was identified in 31 samples from 15 families out of the 2560 samples (1.20%) analyzed for variant Hbs. There were five patients with HbSD disease, three with HbDβ disease, and the remaining 23 were HbD trait. Patients with HbSD disease had a variable clinical presentation with a pair of siblings being transfusion dependent although the age of first blood transfusion was different in the two patients. The one with high HbF started transfusions much later. None of them had symptoms related to sickling. Patients with HbDβ also had a variable presentation with only one of them being transfusion-dependent. All patients with HbSD and HbDβ disease were started on hydroxyurea. Persons with HbD trait were asymptomatic with half of them having normal Hb. The remaining half had mild microcytic hypochromic anemia. All the families with HbD disease were natives of this region and not migrants from other states. Although HbD disease has not been reported from this region in previous studies, clinicians need to be aware of this entity as it can give rise to symptomatic disease in some cases if associated with beta-thalassemia or sickle cell trait.

An Unusual Compound Heterozygosity for Hb O-Arab (HBB: c.364G>A) and Hb D-Los Angeles (HBB: c.364G>C)

We report a newborn with a compound heterozygosity for Hb O-Arab (HBB: 364G>A) and Hb D-Los Angeles (HBB: 364G>C). To the best of our knowledge, the combination of these two hemoglobin (Hb) variants has not been identified and reported before. The variants of the proband and parents were identified by high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). DNA analysis was performed to confirm the variants. The levels of Hb variants of the proband were determined post-partum, at 3 months and 1 year after birth. Blood count analysis after 1 year revealed that the proband had a mild microcytic anemia. Furthermore, HPLC and CE analysis revealed an equal distribution of Hb D-Los Angeles compared to Hb O-Arab at the age of 1 year. The follow-up of the patient, suggested that the Hb combination is clinically silent or mild.

Coinheritance of HbD-Punjab/β+-thalassemia (IVSI+5 G-C) in patient with Gilbert's syndrome

Thalassemia and qualitative hemoglobinopathy are hereditary disorders of Hb synthesis that lead to change in the Hb conformation or a decrease in the synthesis of structurally normal Hb, and consequently, to erythron pathology. Many variants of Hb are unstable or have altered affinity for oxygen, and, in heterozygous form can be associated with clinical and hematological manifestations (hemolytic anemia, hypochromic microcytic anemia, erythrocytosis). HbD-Punjab [β121 (GH4) Glu → Gln; HBB: C.364G> C] is variant of Hb carrying the amino acid substitution in the 121 position of β-globin chain. In all cases reported so far, patients with HbD-Punjab/β+-thalassemia (IVSI+5 G-C) combination experienced typical thalassemia with hypochromic microcytosis. HbD-Punjab was detected by electrophoresis from 37 to 94% of total Hb. The article describes rare clinical case of the cohabitation of HbD-Punjab/β+-thalassemia (IVSI+5 G-C) in a patient with homozygous variant of Gilbert's syndrome observed in AS Loginov Moscow Clinical Scientific Center.

Diagnosis of Compound Heterozygous Hb Tak/β-Thalassemia and HbD-Punjab/β-Thalassemia by HbA2 Levels on Capillary Electrophoresis

A misdiagnosis of β-thalassemia carrier in samples with Hb Tak and HbD-Punjab, the β-variants, can be a cause of inappropriate genetic counseling thus having a new case of β-thalassemia major. A capillary electrophoresis (CE) is very efficient in separating and quantifying HbA₂. In this study, HbA₂ levels of samples which were doubted for compound heterozygous Hb Tak/β-thalassemia or heterozygous HbD-Punjab/β-thalassemia were measured and compared between CE and high performance liquid chromatography (HPLC). The molecular confirmation for Hb Tak, HbD-Punjab and β-thalassemia codons 17 (A > T), 41/42 (-TCTT), 71/72 (+A) and IVSI-nt1 (G > T) mutations and 3.4 kb deletion were also performed. Based on DNA analysis, 3 cases were diagnosed as compound heterozygous Hb Tak/β-thalassemia and one for HbD-Punjab/β-thalassemia. The elevated HbA₂ levels were found in all 4 samples with rages of 4.6-7.3% on CE while those were not found on HPLC. Thus, the elevated HbA₂ measured by CE can be used as a screening parameter for differentiating the homozygote of Hb Tak and HbD-Punjab from the compound heterozygote of these hemoglobinopathies and β-thalassemia.

Coinheritance of hemoglobin D-Punjab and β0-thalassemia 3.4 kb deletion in a Thai girl

Hemoglobin (Hb) D. Punjab [β121(GH4) Glu→Gln; HBB: C.364G>C] and β⁰-thalassemia 3.4 kb deletion are very rare in the Thai population. For the first time, the coinheritance of HbD-Punjab with β⁰-thalassemia 3.4 kb deletion was reported in a 7-year-old Thai girl. She had mild anemia (Hb 115.0 g/L and mean corpuscular hemoglobin 18.1 pg) with red blood cell microcytosis (mean corpuscular volume 52.5 fL). By capillary electrophoresis (CE), HbD-Punjab was found at a migration position of 180 s with the value of 81.9% while the level of HbA₂ was 7.3%. Based on the elevated HbA₂, the molecular analysis for detection of β⁰-thalassemia mutations was performed. The 490 bp amplified fragments from β⁰-thalassemia 3.4 kb deletion was observed. Thus, the coinheritance of HbD-Punjab with β⁰-thalassemia can be found in the Thai population. The HbA₂ measured on CE is a reliable parameter for differentiating the homozygote of HbD-Punjab and compound heterozygote of HbD-Punjab and β⁰-thalassemia.

Co-Inheritance of Haemoglobin D-Punjab and Beta Thalassemia - A Rare Variant

Haemoglobinopathies are a frequent cause of anaemia in Northwestern India due to traditional practices of consanguineous marriages. Haemoglobin D-Punjab is one of the most common subvariants (55%) of haemoglobin D, which can be inherited as a homozygous or a heterozygous trait with other haemoglobinopathies. Though, haemoglobin D-Punjab is commonly seen, a heterozygous trait with beta thalassemia is a very rare presentation. Here, we present a rare case of co-inheritance of haemoglobin D-Punjab and beta thalassemia in a 19-year-old male of Indian origin. He came with gradually progressive generalised weakness with easy fatigability for the past two months. No history of similar complaints in the past. On examination, he was pale and icteric with splenomegaly and Grade I hemorrhoids on systemic examination. On investigation, there was severe anaemia, pancytopenia (mixed picture on smear), vitamin B12 deficiency and raised Lactate Dehydrogenase (LDH). Haemoglobin electrophoresis showed co-inheritance of haemoglobin D-Punjab and beta thalassemia. After Pack Cell Volume (PCV) and B12 supplements, haemoglobin improved. He was counseled about his disease and advised regular follow-up.