1/43. Heavy transfusions and presence of an anti-protein 4.2 antibody in 4. 2(-) hereditary spherocytosis (949delG).BACKGROUND AND OBJECTIVE: A patient with hereditary spherocytosis (HS) was found not to have red cell membrane protein 4.2. This rare form of HS, or 4.2 (-) HS, stems from mutations within the ELB42 or the EPB3 genes. The patient had long suffered from a gastric ulcer and impaired liver function. He had had several dramatic episodes of gastrointestinal tract bleeding and had received numerous transfusions. An antibody against a high frequency, undefined antigen was found, creating a transfusional deadlock. We elucidated the responsible mutation and searched for an anti-protein 4.2 antibody. DESIGN AND methods: Red cell membranes were analyzed by SDS-PAGE and by Western blotting. Nucleotide sequencing was performed after reverse transcriptase-polymerase chain reaction (RT-PCR) and nested PCR. RESULTS: The not previously described mutation was a single base deletion: 949delG (CGCAECC, exon 7, codon 317) in the homozygous state. It was called protein 4.2 Nancy. The deletion placed a non-sense codon shortly downstream so that no viable polypeptide could be synthesized. The patient carried a strong antibody against protein 4.2 as shown by Western blotting. INTERPRETATION AND CONCLUSIONS: The manifestations resulting from the mutation described were compared with the picture of HS stemming from other ELB42 gene mutations. We discuss the mechanism through which the anti-protein 4.2 antibody developed. There was no way to establish or to rule out whether the antibody participated in the transfusional deadlock found in our patient.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
2/43. Coinheritance of two alpha-spectrin gene defects in a recessive spherocytosis family.We studied a recessive hereditary spherocytosis (HS) family from norway in which all four children had haemolytic spherocytosis while spectrin (Sp) deficiency was detected in the proband. Molecular analysis demonstrated that all affected children had inherited the low expression alpha-Sp allele LEPRA (Low Expressed PRAgue) from the father. Haplotyping with a polymorphic dinucleotide repeat for the alpha-Sp gene (alphaVNTR) located in the 3' untranslated region of mRNA showed that all recessive children had inherited the same maternal alpha-spectrin allele. The paternal Sp-alphaLEPRA allele was found in cis of the polymorphic alpha-Sp Bughill allele (alphaBH) characterized by the A970D point mutation in the Sp alpha-chain. This mutation was identified on two-dimensional electrophoresis of Sp tryptic digests as an acidic shift of the alphaII tryptic domains (spots alphaIIa). Analyses of the relative expression of the paternal alpha-Sp Bughill polymorphism in the proband showed that the product of the maternal alpha-Sp gene is almost completely absent from the mature erythrocyte membrane. Comparative analysis between alphaVNTR PCR-amplified from genomic dna and from cDNA showed that the maternal low expression alpha-Sp allele is associated with a decreased amount of mRNA. Results from molecular and biochemical studies showed that all the affected children of this family are compound heterozygous for two different low expression alpha-Sp alleles: an uncharacterized defective alpha-Sp allele on the maternal side and an alphaLEPRA allele tagged by the alphaIIa polymorphism on the paternal side.- - - - - - - - - - ranking = 0.5keywords = membrane (Clic here for more details about this article) |
3/43. Band 3 Cape Town (E90K) causes severe hereditary spherocytosis in combination with band 3 Prague III.Hereditary spherocytosis (HS) is an inherited haemolytic anaemia, characterized by spheroidal, osmotically fragile red blood cells. This disorder exhibits heterogeneity in terms of both clinical severity and underlying molecular defect. We have studied a South African Cape Coloured individual with severe HS owing to a band 3 deficiency caused by two mutations, occurring in trans, in the band 3 gene: a novel variant that we have designated band 3 Cape Town and a previously described mutation, band 3 Prague III. Analysis of erythrocyte membrane proteins indicated a deficiency of both band 3 and protein 4.2, as well as a decreased functional capacity of band 3 to transport anions. Band 3 Cape Town is defined by a GAG-->AAG point mutation at codon 90, substituting a glutamic acid with a lysine in the cytoplasmic domain of the molecule, while band 3 Prague III is a codon 870 CGG-->TGG point mutation, replacing an arginine with a tryptophan in the transmembrane region of band 3. mRNA is transcribed from both mutant alleles, implying that mutant proteins are synthesized, but are either degraded prior to membrane incorporation or insertion is impaired. We conclude that the combination of these two mutations exacerbated the clinical presentation of the proband.- - - - - - - - - - ranking = 1.5keywords = membrane (Clic here for more details about this article) |
4/43. Absence of CD47 in protein 4.2-deficient hereditary spherocytosis in man: an interaction between the Rh complex and the band 3 complex.We present data on a patient of South Asian origin with recessive hereditary spherocytosis (HS) due to absence of protein 4.2 [4.2 (-) HS]. Protein 4.2 cDNA sequence analysis showed the presence of a novel 41-bp frameshift deletion that predicts a truncated peptide designated protein 4.2 Hammersmith. Quantitative reverse transcription-polymerase chain reaction indicated that the mutant mRNA was unstable. Sequencing of protein 4.2 genomic dna revealed that the deletion stems from aberrant splicing. The proband was homozygous for a G>T substitution at position 1747 (cDNA numbering) that activates a cryptic acceptor splice site within exon 11 of the protein 4.2 gene (EPB42). The proband's mother was found to be heterozygous for this substitution. Unlike protein 4.2 null mice, the proband's red cells showed no evidence for abnormal cation permeability. Quantitation of red cell membrane proteins was carried out by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting, and flow cytometric measurement. CD47, a protein associated with the Rh complex, was markedly reduced to about 1% (in the proband) and 65% (in the mother) that found in healthy controls. The Rh-associated glycoprotein migrated with a higher than normal apparent molecular weight on SDS-PAGE. There was no obvious reduction in Rh polypeptides. These observations indicate that protein 4.2 and CD47 interact in the human red cell membrane. They provide further evidence for an association between the band 3 complex (band 3, ankyrin, protein 4.2, glycophorin A) and the Rh complex (Rh-associated glycoprotein, Rh polypeptides, glycophorin B, CD47, LW) and define a point of attachment between the Rh complex and the red cell cytoskeleton.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
5/43. beta-spectrin Sao PauloII, a novel frameshift mutation of the beta-spectrin gene associated with hereditary spherocytosis and instability of the mutant mRNA.Hereditary spherocytosis (HS) is a common inherited anemia characterized by the presence of spherocytic red cells. Defects in several membrane protein genes have been involved in the pathogenesis of HS. beta-spectrin-related HS seems to be common. We report here a new mutation in the beta-spectrin gene coding region in a patient with hereditary spherocytosis. The patient presented acanthocytosis and spectrin deficiency and, at the dna level, a novel frameshift mutation leading to HS, i.e., a C deletion at codon 1392 (beta-spectrin Sao PauloII), exon 20. The mRNA encoding beta-spectrin Sao PauloII was very unstable and the mutant protein was not detected in the membrane or in other cellular compartments. It is interesting to note that frameshift mutations of the beta-spectrin gene at the 3' end allow the insertion of the mutant protein in the red cell membrane, leading to a defect in the auto-association of the spectrin dimers and consequent elliptocytosis. On the other hand, beta-spectrin Sao PauloII protein was absent in the red cell membrane, leading to spectrin deficiency, HS and the presence of acanthocytes.- - - - - - - - - - ranking = 2keywords = membrane (Clic here for more details about this article) |
6/43. Extramedullary hematopoiesis in hereditary spherocytosis deficient in ankyrin: a case report.Hereditary spherocytosis (HS) is a common inherited hemolytic anemia due to red cell membrane defects. Extramedullary hematopoiesis is a compensatory response to insufficient bone marrow blood cell production. The preferred sites of extramedullary hematopoietic involvement are the spleen, liver, and lymph nodes, but in HS the posterior paravertebral mediastinum is also commonly involved. A nonsplenectomized 74-year-old man with mild HS, with primary deficiency in ankyrin, was found by magnetic resonance imaging to have thoracic paravertebral hematopoietic masses. The patient showed high serum levels of erythropoietin, which may have played a role in the development of extramedullary hematopoietic masses through a continuous hematopoietic stimulus to erythroid cells in the propositus. The long-standing history of respiratory infections and of hypoxia in the propositus may have been an additional etiological factor.- - - - - - - - - - ranking = 0.5keywords = membrane (Clic here for more details about this article) |
7/43. Study of a kindred with hereditary spherocytosis and glyceraldehyde-3-phosphate dehydrogenase deficiency.A patient with hereditary spherocytosis (HS) was found to have glyceraldehyde-3-phosphate dehydrogenase (G3PD) deficiency by electrophoresis of the isolated red cell membranes on polyacrylamide gels with sodium dodecyl sulfate (PAGE SDS) as demonstrated by a diminished band 6 (G3PD) and confirmed by specific enzyme assay. Thirteen members of his family were studied: four were normal, two had HS alone, three had G3PD deficiency alone, and four had both HS and G3PD deficiency. G3PD deficient kindred members were probably heterozygous, since their red cell enzyme, while qualitatively normal, was present in half normal amounts. The G3PD deficiency alone was asymptomatic, and there was no evidence that the combination of HS with G3PD deficiency increased the clinical severity of the disease. However, G3PD deficiency, when combined with HS, was associated with an increase in protein band 4.5 on PAGE SDS. This band was also increased by incubation of normal red cells without glucose, and appeared to be a protein absorbed to the membrane as a consequence of metabolic stress. Hence, red cells with the combined abnormalities of both HS and G3PD deficiency showed signs of the exceptional metabolic stress to which they were exposed.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
8/43. association of hereditary spherocytosis with familial adenomatous polyposis in a pedigree: a new syndrome or coincidence?No association of familial adenomatous polyposis (FAP) and hereditary spherocytosis (HS) has been reported, both of which are inherited in an autosomal dominant manner. We present the first reported case of FAP with spherocytosis and construct the family pedigree. In the patient's pedigree, both FAP and spherocytosis were inherited in an autosomal dominant trait. In the 34-year-old Japanese proband's leukocytes, we found no abnormal chromosomal band, and a germline mutation of the APC gene was not detected. All possible genes reported to be linked to HS were located far from chromosome 5q on which the APC gene is located. Although it is unknown if erythrocyte membrane disorder is an additional phenotype of FAP, to the best of our knowledge, this is the first documentation of FAP associated with spherocytosis.- - - - - - - - - - ranking = 0.5keywords = membrane (Clic here for more details about this article) |
9/43. Hereditary spherocytosis (HS) due to loss of anion exchange transporter.BACKGROUND. Hereditary spherocytosis encompasses a heterogenous group of inherited disorders due to alteration of r.b.c. surface/volume ratio. spectrin deficiency is the most common observed defect. We analyzed a case of HS associated with band 3 deficiency without spectrin reduction. methods. In the study of a family originating from southern italy, we show that a 20% deficiency of band 3 with normal spectrin content may be responsible for dominantly inherited hereditary spherocytosis (HS). The proband is a 12 years old girl consulting for jaundice, chronic anaemia and splenomegaly. Her mother had a similar haematologic phenotype. RESULTS. Electrophoretic analysis of erythrocyte membrane proteins showed a deficiency in band 3 protein. Band 3 protein chymotryptic fragments, deglycosylated band 3, and its isolated cytoplasmic domain, all displayed normal electrophoretic migrations. Furthermore, the tryptic peptides profile of the cytoplasmic domain of the protein did not demonstrate any abnormality, nor did the amino acid composition of the peptides. Analysis of the membrane proteins during erythrocyte ageing, evaluated in density-fractionated red cells, showed that band 3 content was normal in the lighter fraction, whereas in the denser fraction band 3 deficiency was more pronounced than in membranes from non fractionated red blood cells. CONCLUSIONS. This case describes HS due to anion exchange transporter deficiency. Our results on fractioned red cells support the hypothesis that the defect was probably due to a band 3 protein loss during cell ageing and not to a primitive quantitative defect.- - - - - - - - - - ranking = 1.5keywords = membrane (Clic here for more details about this article) |
10/43. Homozygosity for dominant form of hereditary spherocytosis.A 6-month-old male infant with hereditary spherocytosis (HS) who was the first child of a cousin marriage is presented. The patient had splenomegaly and severe anaemia. Examination of the peripheral blood smear revealed spherocytes and the osmotic fragility of red blood cells was greatly increased. physical examination of the parents revealed that both parents had mild anaemia, jaundice and splenomegaly. Their peripheral blood smears showed spherocytes and a few acanthocytes. osmotic fragility of red blood cells of both parents were increased. Red cell membrane electrophoresis indicated a deficiency of ankyrin in the propositus; mild deficiency was also detected in both parents. Electrophoretic patterns of red cell membrane proteins suggested that the child was homozygous for the dominant form of HS associated with ankyrin deficiency, while both parents had the simple dominant form of the disease. Red blood cell transfusions were given to the patient starting at the age of 1 month until splenectomy was performed at the age of 1 year that resulted in complete haematological response. This observation indicates that homozygosity for dominant type of HS associated with ankyrin deficiency is life compatible and splenectomy may cure the anaemia.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
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