The unstable Hb Hammersmith or alpha 2 beta 2(42)(CD1)Phe----Ser observed in an Indian child; identification by HPLC and by sequence analysis of amplified DNA

Successful Treatment of a Child with Hemoglobin Hammersmith with Hematopoietic Stem Cell Transplantation

Hemoglobin (Hb) Hammersmith, formed by serine substitution for phenylalanine at residue 42 in the beta-globin chain, is a very rare variant of unstable hemoglobin with low oxygen affinity. For patients with hemoglobinopathies, it is well-established that hematopoietic stem cell transplantation provides a complete cure, but the literature on its role for those with Hb Hammersmith is limited. A seven-month-old girl who was examined for anemia and splenomegaly was followed up for congenital hemolytic anemia. The patient with visible cyanosis of the lips and whose p50 was low in blood gas was diagnosed with Hb Hammersmith through the DNA sequence analysis. During the follow-up, frequent blood transfusions had to be given due to anemia aggravated by infections. Following a successful hematopoietic stem cell transplant from an HLA-matched sibling, the patient completely recovered from Hb Hammersmith. The case is presented because of its rarity.

Successful haploidentical hematopoietic stem cell transplantation (HSCT) and durable engraftment by repeated donor lymphocyte infusions for a Chinese patient with transfusion-dependent hemoglobin (Hb) Hammersmith and massive splenomegaly

BACKGROUND

Hemoglobin (Hb) Hammersmith is a rare form of unstable β-chain hemoglobinopathy causing hemolytic anemia. This rare event led to a more serious transfusion-dependent phenotype in a patient. It was successfully cured by haploidentical hematopoietic stem cell transplantation (HSCT).

METHODS AND RESULTS

A 9-year-old mainland Chinese male with a history of neonatal unconjugated hyperbilirubinemia was diagnosed to have hemoglobin (Hb) Hammersmith. He required regular blood transfusion but was unable to be transfused to desired parameters for 8 years prior to transplant due to social and geographical reasons. He subsequently developed marrow hyperplasia and progressive splenomegaly (down to umbilicus level), suggestive of extramedullary hematopoiesis. Eventually, the family came to Hong Kong and complied to a more intensive transfusion regimen and preconditioning chemotherapy 3 months prior to transplant. He underwent haploidentical HSCT using paternal TCRαβ/CD45RA-depleted graft but suffered from graft rejection, despite splenic irradiation for massive splenomegaly. It was successfully salvaged with second HSCT with unmanipulated graft from the same donor with additional serotherapy and donor lymphocyte infusions.

CONCLUSION

Allogenic haploidentical HSCT for hemoglobin Hammersmith is feasible but adequate immunosuppression during conditioning is crucial. Precise adoptive cell therapy can promote durable engraftment.

Consideration of Splenectomy in Unstable Hemoglobinopathy: A Case Report of Hb Hammersmith (HBB: c.128T>C)

A 5-year-old female has been diagnosed with Hb Hammersmith (HBB: c.128T>C) and has required three blood transfusions thus far, with hemoglobin (Hb) levels dropping as low as 5.4 g/dL. An elective splenectomy is now being considered in order to reduce hemolysis and the need for transfusions. Of 18 previously reported cases of Hb Hammersmith, eight patients have reportedly undergone splenectomy, with only four of those studies reporting clinical improvement. Therefore, the role of splenectomy in unstable hemoglobinopathies remains unclear, but seems to be a promising option in Hb Hammersmith.

Case report: prenatal diagnosis of Hb Hammersmith [β42(CD1)Phe→Ser; HBB: c.128T > C] in a family with an adult male patient

Hb Hammersmith [β42(CD1)Phe → Ser; HBB: c.128T > C] is a rare, unstable hemoglobin (Hb) variant. In this case report, we describe another male case of Hb Hammersmith. A 39-year-old male had hemolytic anemia, cyanosis and splenomegaly since 6 months after birth. He passed the disease allele to his daughter, a 3-year-old girl, who also had hemolytic anemia and splenomegaly. This mutation was not identified in the parents and two brothers of the father. Early prenatal diagnosis was performed in the second pregnancy in this family. This is the first case of Hb Hammersmith in an adult male patient.

DENATURING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY: AN EFFICIENT SCREENING APPROACH IN THE GENETIC DIAGNOSIS OF HEMOGLOBIN HAMMERSMITH

In this study we here present the first report of the detection of the rare beta-thalassemia mutation in the Taiwanese population: Hemoglobin Hammersmith (Hb Hammersmith). The mutation was detected by denaturing high-performance liquid chromatography (DHPLC) screening followed by automated direct sequencing. The mutation was found in an affected woman and her immature female fetus in the heterozygous state. Molecular abnormality of Hb Hammersmith results from an abnormal beta chain with an amino acid substitution (condon 42, TTT→TCT, Phe→Ser) in the beta-globin (HBB) gene with the clinical presentation of hemolytic anemia. Given known wide spectrum of beta-thalassemia alleles in the Taiwanese population, the present report further confirmed the high heterogeneity rate. This result indicated that the importance of the efficient screening approach by DHPLC for genetic diagnosis in beta-thalassemia.

A case report of a male patient with Hb Hammersmith [β42(CD1)Phe→Ser, TTT>TCT]

All Hb Hammersmith [β42(CD1)Phe→Ser, TTT>TCT] patients reported so far have been female, suggesting that this condition may occur as a negative, fatal intrauterine selection against males. In this case report, we describe a male case of Hb Hammersmith. A 6-month-old male patient, born from ovum donation, presented with hemolytic anemia and cyanosis. Hemoglobin (Hb) electrophoresis revealed decreased Hb A (54.0%) and Hb A(2) (0.3%) and markedly increased Hb F (45.7%) levels. Direct sequencing revealed a missense mutation in the HBB gene, c.128T>C (p.Phe42Ser), which is known as Hb Hammersmith. This mutation was not identified in any of this patient's family members. This is the first case of Hb Hammersmith in a male patient, and this study demonstrates that Hb Hammersmith is likely a non fatal condition for males during the intrauterine period.

Hemoglobin Hammersmith [beta 42(CD1) Phe --> Ser] causing severe hemolytic anemia in a Japanese girl

Hemoglobin Hammersmith, a rare, unstable hemoglobin variant, was diagnosed in a 9-year-old Japanese girl. She presented with the typical manifestations of this disorder, including neonatal hyperbilirubinemia, followed by progressive hepatosplenomegaly, jaundice, and bilirubinuria. Because of severe hemolytic anemia, she received transfusions of red blood cells every 3 to 4 weeks. However, she underwent splenectomy at the age of 4 years and has continued to be in partial remission without requiring further transfusions. DNA sequence analysis of the polymerase chain reaction-amplified beta-globin gene revealed a point mutation (T --> C) in the second nucleotide of the 42nd codon of the beta-globin chain (beta 42(CD1) Phe --> Ser).

Hb Hammersmith [beta 42(CD1) Phe-->Ser]: occurrence as a de novo mutation in black monozygotic twins with multiple congenital anomalies

PURPOSE

To present the occurrence of Hb Hammersmith as a de novo mutation in African-American twins with multiple congenital anomalies.

METHODS

Standard hematologic methods were used. The presence of an unstable Hb variant was confirmed by brilliant cresyl blue staining and an isopropanol stability test. Hb Hammersmith was confirmed by the sequencing of polymerase chain reaction-amplified beta-globin gene.

RESULTS

The presence of Hb Hammersmith was confirmed in female monozygotic twins of African-American origin with congenital Heinz body hemolytic anemia and multiple congenital anomalies. The variant occurred as a de novo mutation in the twins.

CONCLUSION

This report describes the occurrence of Hb Hammersmith [B42(CD1)Phe-->Ser] in African-American twins. As with the other reported cases, both twins were female. In addition to Heinz body hemolytic anemia, a low arterial O2 saturation in the proposita was shown by pulse oximetry. Multiple congenital anomalies involving various systems were also found in both twins.

Haemoglobin Hammersmith precludes monitoring with conventional pulse oximetry

We report a case of a 15-yr-old North American Indian female with haemoglobin Hammersmith, scheduled for elective tonsillectomy, whose arterial oxygen saturation could not be reliably monitored perioperatively because of technical limitations of conventional dual wavelength pulse oximetry. The patient was chronically icteric. She had an atrial septal defect with a small L-->R shunt demonstrated by echocardiography. On arrival in the operating room pulse oximetry (Nellcor-Model N100) demonstrated a saturation of 45% whilst breathing room air. Her oxygen saturation increased to 60% whilst breathing 100% oxygen via a face mask. An arterial blood gas performed whilst breathing 100% oxygen revealed a PaO2 of 418 mmHg. Tonsillectomy was completed uneventfully under general anaesthesia. The pulse oximeter did not provide any clinically useful information throughout the case. In conclusion, conventional dual wavelength pulse oximeters cannot give an accurate estimate of oxygenation in patients with haemoglobin Hammersmith. Assessment of oxygenation in these patients requires alternative monitoring techniques.

The structure and function of normal and abnormal haemoglobins

This chapter reviews general aspects of the normal human haemoglobins which include those predominantly present in the embryo, the fetus and newborn baby, and in the normal adult. Special emphasis is given to factors which affect the levels of fetal haemoglobin in the adult because increased percentages of Hb F can be of great benefit to adults with certain haemoglobinopathies such as sickle cell anaemia and beta-thalassaemia. A review of the numerous Hb variants published since the discovery of Hb S in 1959 reveals a steady stream of newly detected abnormalities; most of these are the result of single-point mutations in the alpha-, beta-, gamma-, or delta-globin genes. Of the more than 600 variants listed in a repository, some 200 have clinical significance because of a decreased stability, a change in functional properties, among others. Methodology developed for the detection and quantitation of normal and abnormal Hb components has been greatly modified during the past 30 years; isoelectrofocusing and different fast developing micro chromatographic procedures are the methods of choice. Analyses of DNA isolated from the white cells has become most useful for the final characterization of the variants; this methodology consists of amplification of a desired segment of DNA and identification of a mutation with labelled oligonucleotide probes. Additional methods include sequence determination of this amplified DNA and identification of known mutations with an allele specific amplification procedure.