Elliptocytosis-associated spectrin Rouen (beta 220/218) has a truncated but still phosphorylatable beta chain.

Spectrin Rouen (beta 220/218) is a novel variant, carrying a shortened beta chain with an apparent molecular weight of 218 kDa. It was detected in a French family. All affected members suffered from haemolytic hereditary elliptocytosis. As other shortened beta chain variants described before, the beta Rouen chain is truncated at its carboxyl terminus. Spectrin Rouen is associated with a defect in spectrin dimer self-association and with an abnormally high amount of the alpha I 74 kDa peptide following partial tryptic digestion. Dimer reconstitution experiments from normal and abnormal purified Sp subunits indicated that the increased alpha I 74 kDa fragment is induced by the altered beta chain. However, spectrin Rouen is different from other mutants with a truncated beta chain in several respects: its amount is low (less than 10%) and the spectrin dimer self-associated defect is mild. Critically, the beta Rouen chain has retained the ability of undergoing phosphorylation, even though it is modified in its C-terminal region. These results, compared to those obtained with beta 220/214 spectrin Le Puy and beta 220/216 spectrin Nice, allowed better localization of the beta chain sites that can be phosphorylated by a membrane-bound casein kinase.     

Point mutation in the beta-spectrin gene associated with alpha I/74 hereditary elliptocytosis. Implications for the mechanism of spectrin dimer self-association.

alpha I/74 hereditary elliptocytosis (HE) is a subgroup of HE in which patients exhibit an impaired self-association of spectrin dimers and an abnormal proteolytic cleavage of the alpha I domain of spectrin. We studied a family in which the proband presented with a severe neonatal hemolytic anemia with poikilocytosis. Biochemical analysis of erythrocytes from the proband and his family members allowed us to ascertain a diagnosis of homozygosity for alpha I/74 HE in the proband and heterozygosity in his parents and several of their offspring. Results of polymorphism linkage analysis suggested that the defect in this family was located in beta rather than alpha spectrin. We analyzed the 3' end of the beta-spectrin gene of the proband and detected a mutation that changes a codon for alanine to one for proline. Allele-specific oligomer hybridization on slot blots of DNA from other family members confirmed the presence of the mutation only in members heterozygous for the disorder. This is the first example of a point mutation in the beta-spectrin chain that is associated with defective spectrin dimer self-association and an abnormal proteolytic cleavage of the alpha chain. Based on this finding, we propose a model for the mechanism of interaction between the alpha- and beta-spectrin chains.     

Spectrin Nice (beta 220/216): a shortened beta-chain variant associated with an increase of the alpha I/74 fragment in a case of elliptocytosis

We describe a new spectrin variant with a truncated beta-chain. It was discovered in a 17-year-old white boy presenting with intermittent jaundice and spleen enlargement. He also displayed numerous smooth elliptocytes. On sodium dodecyl sulfate-polyacrylamide gel, the truncated beta-chain (beta'-chain) appeared as an additional band of approximately 216 kilodaltons, migrating between spectrin beta-chain and ankyrin. It represented 30% of total beta-chain. The beta'-chain reacted with an antispectrin beta-chain monoclonal antibody. It failed to become phosphorylated when ghosts were incubated in the presence of [gamma-32P] adenosine triphosphate. Whole spectrin tetramerization was defective since the amount of spectrin dimer was increased in spectrin crude extract and the association constant of the spectrin dimer self- association was decreased. Spectrin whole tetramer isolated from spectrin crude extracts contained small quantities of beta'-chain. Spectrin tryptic peptides showed an increase of the 74,000-dalton fragment at the expense of the 80,000-dalton fragment. So far, the latter abnormality has been used to characterize a number of cases of hereditary elliptocytosis or pyropoikilocytosis with no other apparent change. In the present case, we consider that the abnormality is a consequence of the beta-chain alteration. The parents seemed asymptomatic. As a result, we regard this new spectrin variant as deriving from a de novo mutation.     

Percutaneous mitral commissurotomy for restenosis after surgical commissurotomy: late efficacy and implications for patient selection

OBJECTIVES: The results of percutaneous mitral commissurotomy were assessed in patients with restenosis after surgical commissurotomy. BACKGROUND: Balloon dilation is feasible in patients with restenosis after surgical commissurotomy, but little is known about its late efficacy. METHODS: We studied 232 patients who had undergone percutaneous mitral commissurotomy a mean of 16 +/- 8 years after surgical commissurotomy. Mean age was 47 +/- 14 years; 81 patients (35%) had valve calcification. All patients had restenosis with bilateral commissural fusion as assessed by echocardiography. Technical failure occurred in 9 patients and the procedure used a single balloon in 7 patients, a double balloon in 95, and the Inoue balloon in 121. RESULTS: Complications were death in 1 patient (0.4%) and mitral regurgitation >2/4 in 10 (4%); 191 patients (82%) had good immediate results (valve area > or =1.5 cm2 without regurgitation >2/4). Predictors of poor immediate results in multivariate analysis were older age (p < 0.001), lower initial valve area (p = 0.01) and the use of the double-balloon technique (p = 0.015). In the 175 patients who underwent follow-up, 8-year survival without operation and in New York Heart Association class I or II was 48 +/- 5%, and 58 +/- 6% after good immediate results. In this latter group, poor late functional results were predicted by higher cardiothoracic index (p < 0.0001), previous open-heart commissurotomy (p = 0.05) and lower final valve area (p < 0.0001) in a multivariate Cox model. CONCLUSIONS: Percutaneous mitral commissurotomy is safe and provides good immediate results in selected patients with restenosis after surgical commissurotomy. After good immediate results, the conditions of more than half of the patients remained improved at 8 years, enabling reoperation to be deferred.     

Aberrant pattern of red cell membrane and cytosolic proteins in a case of congenital dyserythropoietic anaemia

We report an unusual case of congenital dyserythropoietic anaemia (CDA). The propositus is a 25-year-old gipsy female presenting with a recessively inherited haemolytic anaemia. The diagnosis of CDA was based on erythrokinetic data and the morphological appearance of the erythroid precursors. The direct assay of HEMPAS antigen was negative. In peripheral blood there were 15% dacryocytes. The red cell membrane protein pattern was dramatically altered, with four major aberrant bands. Band a (mol wt 86,000) was at the lower edge of band 3, band b (mol wt 82,000) was below band 3, band c (68,000) and band d (67,000) were below band 4.2. In addition, there was an array of aberrant minor bands below band d. Gel densitometric determinations and immunological characterization showed that these bands did not derive from any of the major components of the membrane. In fact, membrane proteins appeared normal in many respects, although periodic acid-Schiff staining revealed an apparent decrease of sialoglycoproteins. The major aberrant bands a, b and c occur in very low amounts in controls. These bands, as well as band d, also exist in normal cytosol and were strongly increased in the propositus.     

Immediate and mid-term results of repeat percutaneous mitral commissurotomy for restenosis following earlier percutaneous mitral commissurotomy.

AIMS: This study assessed the results of repeat percutaneous mitral commissurotomy for mitral restenosis following a first procedure. METHODS AND RESULTS: Repeat balloon commissurotomy was performed in 53 patients who had symptomatic restenosis a mean of 6+/-2 years (2-11) after a successful first procedure; seven patients had mildly calcified valves. All patients had restenosis with a fusion of both commissures as assessed by echocardiography. A double-balloon was used in one case and the Inoue technique in 52. Complications were stroke in one patient and severe mitral regurgitation (Sellers grade 3) in two. Valve area increased from 1.03+/-0.22 to 1.82+/-0.21 cm(2)(P<0.0001) as assessed by planimetry. Good immediate results, defined as valve area >/=1.5 cm(2)with no regurgitation >2/4, were obtained in 48 patients (91%). The 5-year survival rate without operation and in NYHA class I or II was 69+/-11% in the whole population, and 76+/-11% in the 48 patients who had had good immediate results. CONCLUSION: This study suggests that repeat balloon commissurotomy is a valid treatment for symptomatic restenosis after a first successful procedure. It gives good results in patients selected on the basis of favourable characteristics and the echocardiographic analysis of the mechanism of restenosis.     

A common type of the spectrin alpha I 46-50a-kD peptide abnormality in hereditary elliptocytosis and pyropoikilocytosis is associated with a mutation distant from the proteolytic cleavage site. Evidence for the functional importance of the triple helical model of spectrin.

We studied nine individuals from five unrelated families with alpha I/46-50a hereditary elliptocytosis (HE) or hereditary pyropoikilocytosis (HPP), including one of the original HHP probands first reported by Zarkowsky and colleagues (1975. Br. J. Haematol. 29:537-543). Biochemical analysis of erythrocyte membrane proteins from these patients revealed, as a common abnormality, the presence of the alpha I/46-50a peptide after limited tryptic digestion of spectrin. The polymerase chain reaction was utilized to study the structure of the DNA encoding the alpha I domain of spectrin in the affected individuals. The DNA sequence of the alpha-spectrin gene encoding the region of the alpha-spectrin chain surrounding the abnormal proteolytic cleavage site was normal. We identified a point mutation causing the replacement of a highly conserved leucine residue by proline at position 207 in the alpha-spectrin chain, a site 51 residues to the amino-terminal side of the abnormal proteolytic cleavage site. Analysis of the proposed triple helical model of spectrin repeats reveals that the mutation occurs in helix 2 at a position directly opposite the abnormal proteolytic cleavage site in helix 3, making this the first report of a mutation occurring in helix 2 of a repeat in the alpha I domain of spectrin. These results add to the molecular heterogeneity of mutations associated with HE/HPP and provide further support for the proposed triple helical model of spectrin. Disruption of this proposed alpha-helical structure by helix-breaking proline substitutions may result in a functionally defective spectrin chain.