Stomatocytosis Research Articles

Clinical features of hereditary stomatocytosis: 12 cases report and literatures review

Clinical features of hereditary stomatocytosis: 12 cases report and literatures review

\u2018Gardos Channelopathy\u2019: a variant of hereditary Stomatocytosis with complex molecular regulation

The Gardos channel is a Ca2+ sensitive, K+ selective channel present in several tissues including RBCs, where it is involved in cell volume regulation. Recently, mutations at two different aminoacid residues in KCNN4 have been reported in patients with hereditary xerocytosis. We identified by whole exome sequencing a new family with two members affected by chronic hemolytic anemia carrying mutation R352H in the KCNN4 gene. No additional mutations in genes encoding for RBCs cytoskeletal, membrane or channel proteins were detected. We performed functional studies on patients’ RBCs to evaluate the effects of R352H mutation on the cellular properties and eventually on the clinical phenotype. Gardos channel hyperactivation was demonstrated in circulating erythrocytes and erythroblasts differentiated ex-vivo from peripheral CD34+ cells. Pathological alterations in the function of multiple ion transport systems were observed, suggesting the presence of compensatory effects ultimately preventing cellular dehydration in patient’s RBCs; moreover, flow cytometry and confocal fluorescence live-cell imaging showed Ca2+ overload in the RBCs of both patients and hypersensitivity of Ca2+ uptake by RBCs to swelling. Altogether these findings suggest that the ‘Gardos channelopathy’ is a complex pathology, to some extent different from the common hereditary xerocytosis.

A Review of 7 Cases of Laparoscopic Cholecystectomy for Pediatric Cholecystolithiasis.

Pediatric cholecystolithiasis is a relatively rare disease, but it is recently increasing in Japan. Laparoscopic cholecystectomy (LC) is a standard procedure for cholecystolithiasis not only in adults but also in children, and we are aggressively introducing single-incision laparoscopic cholecystectomy (SILC) at our hospital. We reviewed the patient characteristics, operation procedures and outcomes of 7 children (15 years old and under) with cholecystolithiasis who underwent LC in our hospital between August 1995 and December 2015. The 7 patients included 5 males and 2 females, with a mean age of 8 years 6 months. Underlying diseases were found in 5 patients (cerebral palsy in 2 patients, pancreaticobiliary maljunction with common bile duct stones in 1, acute lymphocytic leukemia in 1, hereditary stomatocytosis in 1), and none were found in the other 2. LC (3 conventional LC and 2 SILC) was performed in 5 of the patients. Laparoscopic choledocholithotomy was performed in 1 patient and laparoscopic splenectomy (LS) was performed in 1 patient at the same time. The mean operative time in all the cases of LC was 108 (70-140) minutes (conventional LC 113 (70-140) min, SILC 100 (90-100) min). Intraoperative cholangiography was performed in 4 cases and omitted in 3 cases. The only postoperative complication was a wound infection in 1 patient. The umbilical skin incision length in the SILC was 2.0 cm. We conclude that LC can be safely performed for children with cholecsytolithiasis, and that SILC is feasible and advantageous in terms of its improved cosmesis.

Inherited and Acquired Modifiers of Iron Status May Dramatically Affect the Phenotypic Expression of Dehydrated Hereditary Stomatocytosis

▪Background: Hereditary stomatocytosis is an inherited disorder of the erythrocyte membrane responsible of chronic hemolytic anemia. Recent advances in the understanding of this group of diseases came from the identification of the molecular basis of this disorder. Mutations in the SLC4A1, FAM38A, RHAG, and SLC2A1 genes have been shown to cause different subtypes of hereditary stomatocytosis. Dehydrated hereditary stomatocytosis (DHSt) is due to mutations in the FAM38A gene coding for the mechanotransduction protein PIEZO1 and to the newly discovered mutations in the KCNN4 gene encoding the Gardos channel. It is important to recognize this entity and differentiate it from hereditary spherocytosis as patients with HSt develop severe and sometimes lethal thromboembolic complications following splenectomy. Also, some patients develop progressive and severe iron overload (IO) despite well compensated hemolysis and no or little transfusion requirement. It is unclear why patients have such different clinical features regarding hemolytic anemia and IO. We describe herein the impact of inherited and acquired modifiers of iron status on the phenotypic expression of DHSt.Patients & Methods: We describe four patients (3 related and 1 unrelated) with proven DHSt due to FAM38A mutations, who displayed varying degrees of iron load.Results: The four reported patients were referred to our specialized outpatient consultation (center of expertise on rare iron overload) for investigation. Their clinical, laboratory and radiological features are summarized in the Table. It is noteworthy that both index cases were initially referred for investigation of hyperferritinemia. Iron levels closely correlated with the degree of hemolysis and with the severity of the clinical complications. One female patient with severe iron overload suffered from chronic anemia, acute hemolytic episodes, and symptomatic gallstones requiring cholecystectomy while one male patient with severe iron overload suffered from a thrombotic event. The two other female patients with no or moderate iron overload had no or mild hemolysis. Genetic modifiers increasing iron stores, such as the presence of the HFE C282Y mutation, and possibly the gender (male), were accompanied with higher liver iron concentration, increased hemolysis and clinical manifestations. On the opposite, females with normal or low iron stores (iron deficiency anaemia (ID) due to gynecologic bleedings) displayed no or mild hemolytic manifestations. It is noteworthy that in the female with ID no clinical or biological manifestations of hemolysis and of stomatocytosis were found initially (normal specialized phenotypic tests). The diagnosis was made by genetic analyses. Restoration of the iron stores resulted in the appearance of biological signs of hemolysis.Conclusion: Iron overload or iron deficiency dramatically alter the clinical presentation of DHST due to PIEZO1 defects. The search for genetic or acquired causes of iron overload (or deficiency) is an important step in the evaluation of the clinical prognosis and the modulation of iron store may help in the management of the patients. [Display omitted] DisclosuresCartron:Roche: Consultancy, Honoraria; Celgene: Honoraria; Gilead: Honoraria; Jansen: Honoraria.

Iron Overload and Cytokine Serum Levels in Congenital Hemolytic Anemias

▪Background: Congenital hemolytic anemias (CHAs) are a heterogeneous group of inherited RBC disorders including membrane and enzyme defects and dyserythropoietic anemias. Iron overload is a well recognized complication of hereditary hemoglobinopathies, both in transfusion-dependent and independent cases. However, little is known in congenital hemolytic anemias, with the exception of anecdotic reports in pyruvate kinase deficiency and dyserythropoietic anemias.Aim: to describe the clinical and hematological features at diagnosis and enrolment, to investigate iron overload by hepatic and cardiac T2* MRI, and to study inflammatory/regulatory cytokine profiles (IL-6, TNF-alpha, IFN-gamma, IL-10, IL-17) and hepcidin levels in patients with CHAs. Confounding factors such as hemocromatosis genotyping, metabolic syndrome, and hepatic viral profile were also considered.Methods: Between July 2015 and April 2016, 38 patients were enrolled (13 hereditary spherocytosis -HS, 3 hereditary stomatocytosis - HSt, 8 congenital dyserythropoietic anemia type II - CDAII, 13 pyruvate kinase deficiency - PKD, 1 glucose-phosphate isomerase deficiency). HS cases were enrolled on the basis of ferritin >300 ng/mL at diagnosis. Cytokine levels were detected in serum by ELISA. Comparisons were made by Students T test (continuous) and Fisher’s exact test (categorical), and correlations by Pearson’s linear coefficient.Results: The main clinical and hematological findings are shown in table. Median Hb values progressively decreased in the 4 groups considered, being close to normal in HS and moderately reduced in CDAII patients, whereas hemolytic parameters were comparable among groups. Consistently with clinical severity, ferritin values were particularly high in CDAII (together with transferrin saturation-TfS) and PKD patients, notwithstanding chelation in about half cases of both groups. Of note, only 2 PKD patients were transfusion-dependent, suggesting that other factors are involved in iron overload. Splenectomy had been performed in 17/38 (44.7%), mainly CDAII. Liver iron concentration (LIC) showed a great heterogeneity in all groups, with a trend towards higher values in CDAII; 16/36 (44%) patients had a LIC>4 mg/g DW (23%, 33%, 38% and 88% in HS, HSt, PKD and CDAII, respectively). Cardiac T2* value was normal in all subjects, with the exception of a HS and a CDAII case. Regarding possible cofactors, 12/16 displayed at least one of the following: 1 homozygous for HFE C282Y and 1 for H63D mutations, 3 HCV+, 4 BMI>25, 2 alcohol abuse, 3 heterozygous for HFE mutations. The following positive correlations were observed at enrolment: LIC and ferritin (r=0.68, p<0.05), LIC and TfS (r=0.34, p=0.05), and cardiac T2* and TfS (r=0.34, p<0.05). Moreover Hb values at diagnosis negatively correlated with LIC (r=0.37, p<0.05). Interestingly, among the 28 cases with ferritin <800 ng/mL, 10 (36%) displayed liver iron overload (LIC>4), of whom 5 with the above listed cofactors. As regards cytokine levels, IL-10 was significantly increased in HS, PKD and CDAII groups compared with normal cases; TNF-alpha was decreased in HS and PKD, and IFN-gamma increased in HS and CDAII. Ferritin values were positively correlated with IL-6 and IFN-gamma, and TfS negatively with IL-6 (r= -0.38, p<0.05). Hepcidin values were slightly increased in CHAs compared with normal controls, and correlated positively with ferritin (r=0.33; p<0.05), and negatively with TfS (r= -0.56; p<0.001). Finally, hepcidin levels were positively correlated with IL-6 (r=0.62; p<0.001), and negatively with IFN-gamma (r=0.3; p<0.05).Conclusion: Iron overload is highly prevalent in CHAs, particularly in PKD and CDAII, is independent from transfusion support, and is also observed in cases with ferritin <800 ng/mL. T2* MRI is the gold standard approach to evaluate iron overload in CHAs (as in other congenital anemias) and its use is advisable, particularly in the presence of cofactors, for early chelation. Cytokine studies suggest the existence of a positive loop among ferritin, hepcidin, and inflammatory cytokines such as IL-6 and IFN-gamma, and of a negative loop among TfS, hepcidin, and the same inflammatory cytokines. These findings disclose important hints to understand the multiple biological mechanisms of iron overload, and support the rationale for new emerging therapies. [Display omitted] DisclosuresBarcellini:Agios: Consultancy.

New insights on hereditary erythrocyte membrane defects.

After the first proposed model of the red blood cell membrane skeleton 36 years ago, several additional proteins have been discovered during the intervening years, and their relationship with the pathogenesis of the related disorders have been somewhat defined. The knowledge of erythrocyte membrane structure is important because it represents the model for spectrin-based membrane skeletons in all cells and because defects in its structure underlie multiple hemolytic anemias. This review summarizes the main features of erythrocyte membrane disorders, dividing them into structural and altered permeability defects, focusing particularly on the most recent advances. New proteins involved in alterations of the red blood cell membrane permeability were recently described. The mechanoreceptor PIEZO1 is the largest ion channel identified to date, the fundamental regulator of erythrocyte volume homeostasis. Missense, gain-of-function mutations in the PIEZO1 gene have been identified in several families as causative of dehydrated hereditary stomatocytosis or xerocytosis. Similarly, the KCNN4 gene, codifying the so called Gardos channel, has been recently identified as a second causative gene of hereditary xerocytosis. Finally, ABCB6 missense mutations were identified in different pedigrees of familial pseudohyperkalemia. New genomic technologies have improved the quality and reduced the time of diagnosis of these diseases. Moreover, they are essential for the identification of the new causative genes. However, many questions remain to solve, and are currently objects of intensive studies.

Hereditary stomatocytosis: advances in understanding the pathogenesis of dehydrated forms

Hereditary stomatocytosis: advances in understanding the pathogenesis of dehydrated forms

A hypothesis of target cell formation in sickle cell disease

A fraction of erythrocytes appear as target cells in stained blood smears in sickle cell disease, due to a inheritance of the hemoglobin variant Hb S, polymerizing upon deoxygenation. These cells appear in a three dimension as thin cups. A process of their formation in this disease is proposed based on a band 3-based mechanism of the erythrocyte shape control, able to explain the erythrocyte echinocytosis by glucose depletion. It indicates that their formation is due to a stomatocytogenic slow outward transport of the dibasic form of endogenous Pi with an H+ by band 3, promoted by the decrease of the Donnan ratio, which decreases cell pH and volume, attributed by a decrease of cell KCl concentration by the higher efflux of K+Cl− cotransport and Ca2+ activation of the Gardos channel. Its implications are briefly discussed with respect to target cells per se, target cell formation in other hemoglobinopathies, acquired and inherited disorders of the lipid metabolism and dehydrated hereditary stomatocytosis as well as a stomatocyte presence in a double heterozygote of Hb S and Hb C and of an involvement of the process of target cell formation in acanthocytosis in acquired and inherited disorders.

PIEZO1 gene mutation in a Japanese family with hereditary high phosphatidylcholine hemolytic anemia and hemochromatosis-induced diabetes mellitus.

Hereditary xerocytosis (HX) or dehydrated hereditary stomatocytosis (DHS) [OMIM 194380], in which PIEZO1 gene mutation has recently been identified, is difficult to diagnose. We report here the discovery of a PIEZO1 gene mutation in a Japanese family (father, daughter, and son) who were previously diagnosed with hereditary high phosphatidylcholine hemolytic anemia (HPCHA). All of the affected family members had non-spherocytic hemolytic anemia associated with severe hemochromatosis-related diabetes mellitus. Although the causative correlation between HPCHA and PIEZO1-gene mutated HX/DHS remains to be clarified, our findings raise an important question as to whether any of the HPCHA cases previously diagnosed in Japan may have in fact been the form of hemolytic anemia known as HX/DHS with PIEZO1 gene mutation.

Disorders of the erythrocyte membrane

Hemolytic anemia due to abnormalities of the erythrocyte membrane comprises an important group of inherited disorders. These include hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis, and the hereditary stomatocytosis syndromes. The erythrocyte membrane skeleton composed of spectrin, actin, and several other proteins is essential for the maintenance of the erythrocyte shape, reversible deformability, and membrane structural integrity in addition to controlling the lateral mobility of integral membrane proteins. These disorders are characterized by clinical and laboratory heterogeneity and, as evidenced by recent molecular studies, by genetic heterogeneity. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Treatment with splenectomy is curative in most patients.

Diagnostic Power of Laser Assisted Optical Rotational Cell Analyzer (LoRRca MaxSis) Evaluated in 118 Patients Affected By Hereditary Hemolytic Anemias

▪Introduction: Hereditary hemolytic anemias (HAs) is a group of heterogeneous disorders mainly due to defects of red cell (RBC) membrane and metabolism. HAs of RBC membrane are classified according to the morphological appearance on a blood smear: the more common are hereditary spherocytosis (HS), elliptocytosis, followed by stomatocytosis (dehydrated, DHSt and overhydrated, OHSt). Among RBC enzyme defects associated with chronic hemolysis, pyruvate kinase (PK) deficiency is the most common, followed by glucose-6-phosphate isomerase (GPI), pyrimidin 5' nucleotidase (P5'N), and more rarely, other enzymes deficiencies. Because of the rarity and heterogeneity of these diseases, diagnosis may be often challenging despite the availability of a battery of laboratory tests. Ektacytometry, and more recently, laser-assisted optical rotational cell analyser (LoRRca MaxSis, Mechatronics Instruments, NL), able to measure RBC deformability in osmotic gradient conditions (Osmoscan), is reported to be a useful tool in the detection of RBC membrane disorders and in particular for the differential diagnosis of HSt. Few data are available in other haemolytic anemias.Methods: We evaluated the diagnostic power of laser-assisted optical rotational cell analyser in 84 cases with RBC membrane disorders (69 HS, 7 HE, 7 DHSt, 1 OHSt) and 26 enzymopathies: 19 PK deficiency (14 not splenectomised), 4 GPI deficiency and 3 P5N deficiency. Moreover, we analysed 8 congenital diserythropoietic anemia type II (CDA II), of whom 3 not splenectomised. A reference curve interval was obtained from 89 healthy controls. The evaluated parameters were: Omin (osmotic value at which the EI reaches its minimum, coinciding with the 50% hemolysis in osmotic fragility assays), EImax (maximal deformability obtained near the isotonic osmolality), and Ohyper (osmotic value at which the EI reaches half of its maximum value, representing cellular hydration status).Results: Considering membrane defects, all the 69 HS, regardless the biochemical defect, showed typical altered ektacytometry curves, with a decreased EImax (0.516±0.05 vs 0.595±0.008 for controls, p<0.0001) and right shifted Omin (167±11.4 vs 143.7±7.2, p<0.0001); the 7 HE cases displayed a trapezoidal feature and a decreased EImax (0.547±0.05 vs 0.595±0.008, p<0.001). Among the hereditary stomatocytosis, the 7 DHSt were characterized by a left-shifted curve (Fig 1a).Concerning RBC enzymopathies, we found that all the GPI deficient cases showed altered enlarged Osmoscan curves associated with significant increased Ohyper (539±36 vs 462±13.4, p<0.0001), whereas not splenectomised patients with PK deficiency showed an Osmoscan curve characterised by an increased EImax (0.601±0.01 vs 0.595±0.008), although not significant (Fig 1b). Osmoscan curve in not splenectomised CDAII falls in the low reference area of normal controls. However, Omin and EImax were signifificantly different from HS patients thus permitting a differential diagnosis (Omin 149.3 ±3.0 vs 167±11.4, p<0.01; EImax 0.578±0.02 vs 0.516±0.05, p<0.05) (Fig 1c).We separately analysed splenectomised and not splenectomised patients. Interestingly, for some diseases (PK, P5N, CDAII and OHSt) Osmoscan curve after splenectomy, falls in a defined atypical area, regardless the pathology (Fig 1d).Conclusion: The Osmoscan curves were diagnostic for all the HS and HE cases analysed, with Omin and EImax parameters significantly different from controls. DHSt cases always showed typical left-shifted curve. Interestingly, Ohyper was firstly described increased in GPI deficiency, offering a new diagnostic tool for this rare enzyme defect. The interpretation of Osmoscan requires caution in splenectomised cases as splenectomy may interfere with the RBC deformability. In conclusion, the Osmoscan analysis performed by LoRRca Maxsis represents a useful and feasible first step screening test in the diagnosis of RBC membrane disorders and other rare haemolytic anemias. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Gardos Channel Mutation Is Associated with Hereditary Dehydrate Stomatocytosis: a Complex Channelopathy

The Gardos channel (KCNN4) is a Ca2+ sensitive, intermediate conductance, K+ selective channel abundant in several tissues including red blood cells (RBC) where it is involved in cell volume regulation (Hoffman et al. 2003, Cahalan et al. 2015).Hereditary dehydrate stomatocytosis (DHSt) is characterized by mild to moderate congenital hemolytic anemia with reticulocytosis and splenomegaly associated with RBC dehydration. Affected RBC are characterized by a nonspecific cation leak, reflected in elevated Na+ content, decreased K+, elevated MCHC and MCV, and decreased osmotic fragility. The definitive diagnosis of DHSt is made by osmotic gradient ektacytometry, which shows a leftward shift of the bell-shaped curve.Heterozygous mutations associated with delayed channel inactivation have been identified for PIEZO1 (Zarychanski et al. 2012), although there are patients lacking a mutation in this gene. Differential diagnosis in hereditary stomatocytosis is important because in DHSt patients, splenectomy is contraindicated due to increased risk of thromboembolic complications.We studied a 40 year-old Italian man, affected since infancy by chronic hemolyitc anemia (Hb 7-9 g/dL, reticulocytes 10%). The unrelated parents and three siblings were healthy with normal hematologic parameters. He was occasionally transfused until splenectomy, performed at the age of 11 years. After splenectomy Hb levels maintained around 10 g/dL, thrombotic events did not occur. Increased ferritin levels (>1000 ng/ml) and moderate iron overload required chelation therapy. Peripheral blood smear showed anysopoikilocytosis with stomatocytes (13%) echinocytes (7%) schistocytes (6%) ellyptocytes (5%) spherocytes (4%). Bone marrow evaluation revealed erythroid hyperplasia with some dyserytrhopoietc changes, in particular binucleated erythroblasts. Eosin 5 maleimide (EMA) binding test was negative; despite the high number of stomatocytes in peripheral blood, the osmotic gradient ektacytometry curve was not suggestive for hereditary xerocytosis.The proband's first daughter, born at term after an uneventful pregnancy, presented with severe anemia (Hb 6.1 g/dL) requiring RBC transfusion at birth and at 4 months; at the age of 1 year she displayed a clinical pattern similar to the one of the father, with median Hb levels of 9 g/dL and no need of transfusions.To uncover the underlying etiologies, all the family members underwent whole exome sequencing. Only one candidate gene, the KCNN4 could be identified: a heterozygous missense mutation (c.1055G>A, p.R352H) was detected as a de novo mutation in the proband, and dominantly transmitted to the daughter. The mutation falling in exon 7 involved in the calmodulin binding domain was predicted to be pathogenic by in silico analysis. Sanger sequencing confirmed the presence of the mutation.Very recently (July 2015), the same mutation in the KCNN4 gene was described by other groups (Rapetti-Mauss et al. 2015; Andolfo et al. 2015). In heterologous expression systems it could be shown that the Ca2+ sensitivity of the mutated Gardos channel was increased.We performed single cell experiments, including patch-clamp recordings in RBCs and precursor cells, Ca2+ fluorescence imaging as well as tracer flux experiments in RBCs of the above described patients and healthy controls to get a mechanistic link between the Gardos channel mutation and the cellular symptoms. Despite the presence of a single mutation in Gardos channel alone, pathological alterations in function of multiple ion transport systems were revealed during these studies.Our findings together with recent reports (Rapetti-Mauss et al. 2015; Andolfo et al. 2015; Glogowska et al. 2015) suggest that the prevalence of mutations in the Gardos channel is higher than previously thought. Therefore it is important to understand the mechanisms implicated by the mutation and to develop reliable diagnostic tools and treatment strategies. DisclosuresNo relevant conflicts of interest to declare.

Dehydrated hereditary stomatocytosis

Dehydrated hereditary stomatocytosis

Impaired PIEZO1 function in patients with a novel autosomal recessive congenital lymphatic dysplasia.

Piezo1 ion channels are mediators of mechanotransduction in several cell types including the vascular endothelium, renal tubular cells and erythrocytes. Gain-of-function mutations in PIEZO1 cause an autosomal dominant haemolytic anaemia in humans called dehydrated hereditary stomatocytosis. However, the phenotypic consequence of PIEZO1 loss of function in humans has not previously been documented. Here we discover a novel role of this channel in the lymphatic system. Through whole-exome sequencing, we identify biallelic mutations in PIEZO1 (a splicing variant leading to early truncation and a non-synonymous missense variant) in a pair of siblings affected with persistent lymphoedema caused by congenital lymphatic dysplasia. Analysis of patients' erythrocytes as well as studies in a heterologous system reveal greatly attenuated PIEZO1 function in affected alleles. Our results delineate a novel clinical category of PIEZO1-associated hereditary lymphoedema.

Novel mutations in PIEZO1 cause an autosomal recessive generalized lymphatic dysplasia with non-immune hydrops fetalis.

Generalized lymphatic dysplasia (GLD) is a rare form of primary lymphoedema characterized by a uniform, widespread lymphoedema affecting all segments of the body, with systemic involvement such as intestinal and/or pulmonary lymphangiectasia, pleural effusions, chylothoraces and/or pericardial effusions. This may present prenatally as non-immune hydrops. Here we report homozygous and compound heterozygous mutations in PIEZO1, resulting in an autosomal recessive form of GLD with a high incidence of non-immune hydrops fetalis and childhood onset of facial and four limb lymphoedema. Mutations in PIEZO1, which encodes a mechanically activated ion channel, have been reported with autosomal dominant dehydrated hereditary stomatocytosis and non-immune hydrops of unknown aetiology. Besides its role in red blood cells, our findings indicate that PIEZO1 is also involved in the development of lymphatic structures.

ICSH guidelines for the laboratory diagnosis of nonimmune hereditary red cell membrane disorders.

Hereditary spherocytosis (HS), hereditary elliptocytosis (HE), and hereditary stomatocytosis (HSt) are inherited red cell disorders caused by defects in various membrane proteins. The heterogeneous clinical presentation, biochemical and genetic abnormalities in HS and HE have been well documented. The need to raise the awareness of HSt, albeit its much lower prevalence than HS, is due to the undesirable outcome of splenectomy in these patients. The scope of this guideline is to identify the characteristic clinical features, the red cell parameters (including red cell morphology) for these red cell disorders associated, respectively, with defective cytoskeleton (HS and HE) and abnormal cation permeability in the lipid bilayer (HSt) of the red cell. The current screening tests for HS are described, and their limitations are highlighted. An appropriate diagnosis can often be made when the screening test result(s) is reviewed together with the patient's clinical/family history, blood count results, reticulocyte count, red cell morphology, and chemistry results. SDS-polyacrylamide gel electrophoresis of erythrocyte membrane proteins, monovalent cation flux measurement, and molecular analysis of membrane protein genes are specialist tests for further investigation. Specialist tests provide additional evidence in supporting the diagnosis and that will facilitate the management of the patient. In the case of a patient's clinical phenotype being more severe than the affected members within the immediate family, molecular testing of all family members is useful for confirming the diagnosis and allows an insight into the molecular basis of the abnormality such as a recessive mode of inheritance or a de novo mutation.

Hereditary stomatocytosis: First case report from Valley of Kashmir

Stomatocytes are erythrocytes with a central slit or mouth-shaped (stoma) area of central pallor when examined on dried smears. In wet preparations, they are uniconcave rather than biconcave, giving them a bowllike appearance. In vitro, stomatocytes are produced by drugs that intercalate into the inner half of the lipid bilayer, thereby expanding the inner lipid surface area relative to that of the outer half of the bilayer. Hereditary stomatocytosis (also known as hereditary hydrocytosis, or overhydrated stomatocytosis) refers to a heterogeneous group of autosomal dominant hemolytic anemias caused by altered sodium permeability of the red cell membrane. We present the first case report of hereditary stomatocytosis in a 10-year-old male from the valley of Kashmir. Only eight families with this condition have been described worldwide.

Hereditary stomatocytosis: First case report from Valley of Kashmir

Hereditary stomatocytosis: First case report from Valley of Kashmir

Abstract 5091: Aneuploidy is in stomatin overexpressed cells

Abstract A 31.5 kDa membrane associated protein which is highly abundant in the lipid rafts is stomatin. Human gene expression profile from UCSC Genome Bioinformatics databank indicates that stomatin is major in the peripheral blood, adipose tissue, muscle, and bone marrow. In the beginning, stomatin was thought to be involved in the disease OHSt (overhydrated hereditary stomatocytosis), and therefore named stomatin. However, later studies did not reveal mechanistic role of stomatin in mediating OHSt by evaluating stomatin gene deleted mice; the function of stomatin is therefore remained unclear. In this study, we found that overexpression of stomatin was able to induce the multinucleated cell formation. Our data also demonstrated that stomatin made in the cytoplasm could be transported outside of the cell and released to the culture medium. While adding the culture medium or condition medium to the cells, which did not contain exogenous stomatin, these cells were also triggered to undergo formation of multinucleated cells. Additionally, the stomatin induced multinucleated cells presented aneuploidy and abnormal centrosome number. Possible mechanisms underlying functions of stomatin that induce multinucleated cells are investigated. Note: This abstract was not presented at the meeting. Citation Format: Jui-Hao Lee, Chi-Hung Lin. Aneuploidy is in stomatin overexpressed cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5091. doi:10.1158/1538-7445.AM2014-5091

The Structure of a Conserved Piezo Channel Domain Reveals a Topologically Distinct β Sandwich Fold

Piezo has recently been identified as a family of eukaryotic mechanosensitive channels composed of subunits containing over 2,000 amino acids, without recognizable sequence similarity to other channels. Here, we present the crystal structure of a large, conserved extramembrane domain located just before the last predicted transmembrane helix of C.elegans PIEZO, which adopts a topologically distinct β sandwich fold. The structure was also determined of a point mutation located on a conserved surface at the position equivalent to the human PIEZO1 mutation found in dehydrated hereditary stomatocytosis patients (M2225R). While the point mutation does not change the overall domain structure, it does alter the surface electrostatic potential that may perturb interactions with a yet-to-be-identified ligand or protein. The lack of structural similarity between this domain and any previously characterized fold, including those of eukaryotic and bacterial channels, highlights the distinctive nature of the Piezo family of eukaryotic mechanosensitive channels.