1/189. Four new mutations in the erythroid-specific 5-aminolevulinate synthase (ALAS2) gene causing X-linked sideroblastic anemia: increased pyridoxine responsiveness after removal of iron overload by phlebotomy and coinheritance of hereditary hemochromatosis. X-linked sideroblastic anemia (XLSA) in four unrelated male probands was caused by missense mutations in the erythroid-specific 5-aminolevulinate synthase gene (ALAS2). All were new mutations: T647C, C1283T, G1395A, and C1406T predicting amino acid substitutions Y199H, R411C, R448Q, and R452C. All probands were clinically pyridoxine-responsive. The mutation Y199H was shown to be the first de novo XLSA mutation and occurred in a gamete of the proband's maternal grandfather. There was a significantly higher frequency of coinheritance of the hereditary hemochromatosis (HH) HFE mutant allele C282Y in 18 unrelated XLSA hemizygotes than found in the normal population, indicating a role for coinheritance of HFE alleles in the expression of this disorder. One proband (Y199H) with severe and early iron loading coinherited HH as a C282Y homozygote. The clinical and hematologic histories of two XLSA probands suggest that iron overload suppresses pyridoxine responsiveness. Notably, reversal of the iron overload in the Y199H proband by phlebotomy resulted in higher hemoglobin concentrations during pyridoxine supplementation. The proband with the R452C mutation was symptom-free on occasional phlebotomy and daily pyridoxine. These studies indicate the value of combined phlebotomy and pyridoxine supplementation in the management of XLSA probands in order to prevent a downward spiral of iron toxicity and refractory anemia. ( info) |
2/189. A novel mutation of the erythroid-specific delta-aminolaevulinate synthase gene in a patient with X-linked sideroblastic anaemia. A novel missense mutation, A1754G, in exon 11 of the erythroid-specific delta-aminolaevulinate synthase gene (ALAS2) was identified in a Japanese male with sideroblastic anaemia. ALAS activity in bone marrow cells of the patient was reduced to 53.3% of the normal control. Consistent with this finding, activity of a bacterially expressed ALAS2 mutant protein harbouring this mutation was 19.5% compared with the normal control, but was increased up to 31.6% by the addition of pyridoxal 5'-phosphate (PLP) in vitro. RFLP analysis with Bsp HI restriction revealed that his mother was a carrier of the mutation. These findings suggest that A1754G mutation was inherited in this family in a manner consistent with X-linked inheritance, and is responsible for sideroblastic anaemia in the patient. ( info) |
3/189. trisomy 21 as the sole abnormality in a refractory anemia with ring sideroblasts. Numerous chromosome abnormalities have been described in myelodysplastic syndromes, but single karyotypic aberrations are much less frequent. We report the case of a 65-year-old woman who presented a trisomy 21 as the sole karyotypic anomaly for a refractory anemia with ring sideroblasts. The nature of such an anomaly is discussed in regard to pathogenesis and prognosis. ( info) |
4/189. thrombocytosis with sideroblastic erythropoiesis: a mixed myeloproliferative myelodysplastic syndrome. Some patients with haematological neoplasms have features which overlap between a myelodysplastic syndrome and a myeloproliferative disorder. Two such patients are reported, both having sideroblastic erythropoiesis and thrombocytosis and one sequentially developing features of atypical chronic myeloid leukaemia, idiopathic myelofibrosis and acute megakaryoblastic leukaemia. The prevalence of thrombocytosis among cases of refractory anaemia with ring sideroblasts may be as high as 15-20% and has implications for choice of therapy. ( info) |
5/189. Sideroblastic anaemia and leukaemia in multiple myeloma. Two patients with IgA myeloma and one patient with kappa light chain disease developed sideroblastic anaemia from two to four years after the initial diagnosis. All had previously received radiotherapy and chemotherapy (melphalan and prednisone). In two patients the myeloma was quiescent when the sideroblastic change occurred. Leukaemia occurred in two patients two and seven months respectively after the diagnosis of sideroblastic anaemia was made. In one of them, the myeloma became active again at the same time. The development of sideroblastic anaemia may be a pre-leukaemic event and may be recognised by the appearance of a dimorphic blood film. ( info) |
6/189. A novel mutation of the erythroid-specific gamma-Aminolevulinate synthase gene in a patient with non-inherited pyridoxine-responsive sideroblastic anemia. A novel missense mutation, G663A, in exon 5 of the erythroid-specific delta-aminolevulinate synthase gene (ALAS2) was identified in a Japanese male with pyridoxine-responsive sideroblastic anemia. Activity of the mutant delta-aminolevulinate synthase protein expressed in vitro was 15.1% compared with the normal control, but was increased up to 34.5% by the addition of pyridoxal 5'-phosphate, consistent with the clinical response of the patient to pyridoxine treatment. The same mutation was also detected in genomic dna from the oral mucosal membrane of the patiet; however, it was not detected in other family member. These findings suggest that this G663A mutation is responsible for sideroblastic anemia in the proband, and may be an index mutation in this pedigree. ( info) |
7/189. sjogren's syndrome terminating as a myeloproliferative disorder. A 59 year old female was diagnosed as having sjogren's syndrome in 1963. A short time later, she developed a refractory sideroblastic anemia. In 1972, she was found to have a preleukemic state with a persistent "shift to the left" of the granulocytic series, terminating early in 1974 as acute myeloblastic leukemia. Although several cases of malignant lymphomata have been described in association with Sjorgen's syndrome, to our knowledge no other example of Sjorgen's syndrome has been described in association with a myeloproliferative disorder. Defective immune surveillance produced by the Sjorgen's syndrome may have permitted the development of the myeloproliferative syndrome. Alternatively, both disorders may have developed from a hemopoietic stem cell defect. ( info) |
8/189. Successful allogeneic bone marrow transplantation for childhood-onset refractory anemia with ringed sideroblasts. Refractory anemia with ringed sideroblasts (RARS) is an extremely rare type of myelodysplastic syndrome in children. We describe a 10-year-old boy with RARS presented with pancytopenia. He remained relatively stable with only a few transfusions until age of 20 years, when he underwent an allogeneic bone marrow transplantation (BMT) because of increased transfusion requirements. He remains in complete chimeric state at 20 months posttransplant with normal hematologic parameters. To our knowledge, this is the first description of successful BMT in a patient with childhood-onset RARS. The indication of BMT for this rare disorder in children is discussed. ( info) |
9/189. Relapsing polychondritis and myelodysplasia: a report of two cases and review of the current literature. Relapsing polychondritis (RP) is a rare multisystem disorder. We describe two case reports of patients with RP, one of whom developed myelodysplasia subtype refractory anaemia (RA) and the other, refractory anaemia with ringed sideroblasts (RARS). We also review the literature of association between RP and haematological disorders. ( info) |
10/189. Refractory anemia with ringed sideroblasts with a low IPSS score progressed rapidly with de novo appearance of multiple karyotypic abnormalities and into acute erythroleukemia (AML-M6A). We report here a case of refractory anemia with ringed sideroblasts (RARS) with a low risk group by the International Prognostic Scoring System (IPSS) at the time of diagnosis but had a rapid disease progression. Although the patient showed a normal male karyotype at the time of RARS diagnosis, his marrow cells had del(5)(q14) and add(17)(p12) abnormalities 2 months after the diagnosis, and later the marrow cells had multiple abnormalities and the patient expired 6 months after the initial diagnosis of RARS. The patient was diagnosed as having RARS with a low risk group by the IPSS classification, however, one should keep in mind that some patients with myelodysplastic syndromes with low risks by either the French-American-British (FAB) classification or the IPSS classification may have progressive disease and subsequential cytogenetic analysis could predict the disease progression. ( info) |