1/74. Southeast Asian ovalocytosis in White persons. We describe two White persons, a girl and her mother, presenting with Southeast Asian ovalocytosis. The child was evaluated for scoliosis. The red cell indices were normal but the cell counter triggered an alarm due to a high fraction of hyperdense red cells. Blood smears showed ovalocytes and ovalostomatocytes. Red cells exhibited a total lack of deformability upon osmotic gradient ektacytometry performed immediately after blood drawing. Analysis of nucleic acids and proteins ascertained a 27 nucleotide deletion, resulting in the loss of amino acids 400 to 408, and the presence in cis of the Memphis I polymorphism. The sulfate transport was diminished by more than 50%. There was no acidosis. in vitro invasion of ovalocytes by plasmodium falciparum was decreased. The mother presented with the same hematological picture. On the whole, the condition was Southeast Asian ovalocytosis in all respects. The present kindred had ancestors who had inhabited islands in the Southwestern indian ocean. ( info) |
2/74. Hereditary elliptical stomatocytosis: a case report. The case described demonstrates the development of elliptical stomatocytosis in a neonate and the appearance of elliptical stomatocytes in her mother whose blood film, before delivery, showed elliptocytosis. Further investigations on both individuals indicated a mild haemolytic anaemia. To our knowledge this is the second reported case of elliptical stomatocytosis. ( info) |
3/74. Distal renal tubular acidosis and high urine carbon dioxide tension in a patient with southeast Asian ovalocytosis. Southeast Asian ovalocytosis (SAO) is the best-documented disease in which mutation in the anion exchanger-1 (AE1) causes decreased anion (chloride [Cl-]/bicarbonate [HCO3-]) transport. Because AE1 is also found in the basolateral membrane of type A intercalated cells of the kidney, distal renal tubular acidosis (dRTA) might develop if the function of AE1 is critical for the net excretion of acid. Studies were performed in a 33-year-old woman with SAO who presented with proximal muscle weakness, hypokalemia (potassium, 2.7 mmol/L), a normal anion gap type of metabolic acidosis (venous plasma pH, 7. 32; bicarbonate, 17 mmol/L; anion gap, 11 mEq/L), and a low rate of ammonium (NH4 ) excretion in the face of metabolic acidosis (26 micromol/min). However, the capacity to produce NH4 did not appear to be low because during a furosemide-induced diuresis, NH4 excretion increased almost threefold to a near-normal value (75 micromol/L/min). Nevertheless, her minimum urine pH (6.3) did not decrease appreciably with this diuresis. The basis of the renal acidification defect was most likely a low distal H secretion rate, the result of an alkalinized type A intercalated cell in the distal nephron. Unexpectedly, when her urine pH increased to 7.7 after sodium bicarbonate administration, her urine minus blood carbon dioxide tension difference (U-B Pco2) was 27 mm Hg. We speculate that the increase in U-B Pco2 might arise from a misdirection of AE1 to the apical membrane of type A intercalated cells. ( info) |
4/74. Analysis of the red cell membrane in a family with hereditary elliptocytosis--total or partial of protein 4.1. In a 12-year-old boy carrying a clinically silent elliptocytosis, we observed a total lack of red cell membrane band 4.1. Band 4.1 was partially absent in the father who also displayed a clinically silent elliptocytosis and, remarkably, in the mother although she presented normal discocytes. Band (2 and 2.1.) phosphorylation was sharply reduced in the three persons examined. In the propositus and his mother, but not in his father, a clearly phosphorylated band appeared at the level of band 4.2. We suggest that the father and the mother carry two distinct alleles affecting differently the interactions within the spectrin-actin protein 4.1 complex. The father's allele is elliptocytogenic in the heterozygous state and, among other molecular alterations, prevents the attachment of protein 4.1. The mother's allele is morphologically silent in the heterozygous state, yet it also affects the binding of protein 4.1, possibly because the latter is shortened. The propositus, being doubly heterozygous, has the same morphological phenotype as his father, but his protein 4.1 electrophoretic phenotype is the addition of both parental phenotypes. The distinct phosphorylation patterns in the region of bands 4.1 and 4.2 are also consistent with the two-allele hypothesis. ( info) |
5/74. Enhanced haemolysis with beta-thalassaemia trait due to the unstable beta chain variant, Hb Gunma, accompanied by hereditary elliptocytosis due to protein 4.1 deficiency in a Japanese family. We identified a Japanese family with a beta-thalassaemia trait and hereditary elliptocytosis (HE). We studied five members of this family. One was normal, one had only the beta-thalassaemia trait, one had heterozygous HE, and two had compound heterozygous beta-thalassaemia trait and HE. The last two had already undergone splenectomy. The molecular profile of beta-thalassaemia was consistent with that of Hb Gunma: codon 127/128CAGGCT(Gln-Ala)--> CCT(Pro). Analysis of erythrocyte membrane proteins revealed a partial deficiency of protein 4.1 in all those with HE, whereas the spectrin content was within the normal range. Each heterozygous family member with either the beta-thalassaemia trait or HE was asymptomatic, whereas the two with both beta-thalassaemia and HE had marked red blood cell deformities and haemolysis. The abnormalities of the red blood cells in patients with the beta-thalassaemia trait might be enhanced by association with HE owing to a protein 4.1 deficiency. ( info) |
6/74. Alpha I/65 hereditary elliptocytosis in southern italy: evidence for an African origin. alpha I/65 Hereditary elliptocytosis (HE) is due to the duplication of TTG codon 154 (leucine) of alpha-spectrin and is associated with a constant haplotype. It was encountered exclusively in African and American Blacks, and in North Africans. We assumed that it diffused from the benin-togo area to Northern africa. We now report two South Italian families with alpha I/65 HE. The phenotype fully conformed to previous descriptions. The mode of transmission was dominant; however, the manifestations were more pronounced when the common, low expression level alpha V/41 allele occurred in trans to the alpha I/65 allele, also conforming to previous records. The mutation underlying alpha I/65 HE turned out to be, again, the duplication of TTG codon 154 and the associated haplotype was the same as that encountered previously ( - ; XbaI, PvuII, MspI). Thus, the alpha I/65 allele found in italy must have been introduced from North africa across the Sicilian channel and would ultimately have originated from the benin-togo area. It would witness the same migratory stream as that followed by the benin type haemoglobin S allele, which is also present in Southern italy. ( info) |
7/74. Red pulp of the spleen in hereditary elliptocytosis. Electron microscopic study of the spleen of an adult with hereditary elliptocytosis demonstrated features of erythrocyte pooling in the splenic cords with decreased red cells in transit through the basement membrane slits between the sinus littoral cells and decreased erythrocytes in splenic sinuses. Cordal reticulum cells, macrophages, and platelets were prominent. light microscopy demonstrated relatively empty sinuses, and electron microscopy confirmed that the sinuses contained variable numbers of intact red cells. The morphology of the splenic red pulp in hereditary elliptocytosis was found to simulate that seen in hereditary spherocytosis but to a lesser degree. ( info) |
8/74. A deletional frameshift mutation of the beta-spectrin gene associated with elliptocytosis in spectrin tokyo (beta 220/216). A novel spectrin variant carrying a truncated beta-chain and designated spectrin tokyo (beta 220/216) is presented. It was associated with elliptocytosis and moderate uncompensated hemolysis. The dimer self-association was reduced. An increase of the alpha I 74-Kd fragment was detected upon partial trypsin digestion. Analysis of cDNA and genomic dna showed a 1-base deletion in codon 2059 (GCC AGC-->GCA GCT; Ala-Ser-->Ala-Ala) that belongs to exon X of spectrin beta-gene. A missense sequence extended down to (new) codon 2075. serine 2060, a potential phosphorylation site, was replaced by alanine. The shortened beta-chain failed to undergo phosphorylation in vitro. spectrin tokyo shared the same stop codon, overlapping normal codons 2076 and 2077 (CTG AAA), as spectrin Nice (beta 220/216), which is caused by a dinucleotide insertion in codon 2046 and contains 2076 amino acids. However, for some reason, spectrin tokyo had a lower incorporation level into the membrane than spectrin Nice. ( info) |
9/74. Homozygous 4.1(-) hereditary elliptocytosis associated with a point mutation in the downstream initiation codon of protein 4.1 gene. We studied a 43 yr-old Spanish patient with homozygous 4.1(-) hereditary elliptocytosis. Any form of protein 4.1 was missing in the red cells. spectrin and actin were slightly, yet significantly, diminished. Alterations appeared at the level of proteins 4.5 and 4.9. glycophorin C was sharply reduced. The abnormal allele was associated with the - -- haplotype (Pvu II, Bgl II, Bgl II, Pvu II, Pvu II). mRNA 4.1(-) had an apparently normal size but was diminished by about two-thirds. Because the abnormal phenotype pertained to the red cell, we sequenced the 4.1 cDNA regions that appear critical to this cell type. The ultimate change turned out to be a point mutation of the downstream translation initiation codon (AUG-->AGG). No disorders in other cell types could be related with certainty to the present 4.1(-) HE allele. ( info) |
10/74. Protein 4.1 deficiency and deletion of chromosome 20q are associated with acquired elliptocytosis in myelodysplastic syndrome. We report a case of myelodysplastic syndrome (MDS), associated with prominent elliptocytosis. A 66-year-old male presented with peripheral pancytopenia, and was diagnosed with MDS [refractory anaemia (RA)]. Apart from marked elliptocytosis, dyshaematopoietic features were not evident in his peripheral blood or hypercellular bone marrow. After 18 months, he had progressed to RA with excess blasts in transformation. Analysis of red blood cell membrane proteins by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed a reduced quantity of protein 4.1 (30% of control). Deletion of chromosome 20q was identified by conventional cytogenetic analysis and fluorescence in situ hybridization. Marked elliptocytosis, persistent for more than 17 months, decreased strikingly after chemotherapy with idarubicin and Ara-C. These findings suggest that acquired elliptocytosis occurred as an unusual morphological feature of MDS, associated with abnormalities of protein 4.1 and chromosome 20q. ( info) |