The Erythrocyte Sedimentation Rate and Its Relation to Cell Shape and Rigidity of Red Blood Cells from Chorea-Acanthocytosis Patients in an Off-Label Treatment with Dasatinib.

BACKGROUND: Chorea-acanthocytosis (ChAc) is a rare hereditary neurodegenerative disease with deformed red blood cells (RBCs), so-called acanthocytes, as a typical marker of the disease. Erythrocyte sedimentation rate (ESR) was recently proposed as a diagnostic biomarker. To date, there is no treatment option for affected patients, but promising therapy candidates, such as dasatinib, a Lyn-kinase inhibitor, have been identified. METHODS: RBCs of two ChAc patients during and after dasatinib treatment were characterized by the ESR, clinical hematology parameters and the 3D shape classification in stasis based on an artificial neural network. Furthermore, mathematical modeling was performed to understand the contribution of cell morphology and cell rigidity to the ESR. Microfluidic measurements were used to compare the RBC rigidity between ChAc patients and healthy controls. RESULTS: The mechano-morphological characterization of RBCs from two ChAc patients in an off-label treatment with dasatinib revealed differences in the ESR and the acanthocyte count during and after the treatment period, which could not directly be related to each other. Clinical hematology parameters were in the normal range. Mathematical modeling indicated that RBC rigidity is more important for delayed ESR than cell shape. Microfluidic experiments confirmed a higher rigidity in the normocytes of ChAc patients compared to healthy controls. CONCLUSIONS: The results increase our understanding of the role of acanthocytes and their associated properties in the ESR, but the data are too sparse to answer the question of whether the ESR is a suitable biomarker for treatment success, whereas a correlation between hematological and neuronal phenotype is still subject to verification.

Acanthocyte Sedimentation Rate as a Diagnostic Biomarker for Neuroacanthocytosis Syndromes: Experimental Evidence and Physical Justification.

(1) Background: Chorea-acanthocytosis and McLeod syndrome are the core diseases among the group of rare neurodegenerative disorders called neuroacanthocytosis syndromes (NASs). NAS patients have a variable number of irregularly spiky erythrocytes, so-called acanthocytes. Their detection is a crucial but error-prone parameter in the diagnosis of NASs, often leading to misdiagnoses. (2) Methods: We measured the standard Westergren erythrocyte sedimentation rate (ESR) of various blood samples from NAS patients and healthy controls. Furthermore, we manipulated the ESR by swapping the erythrocytes and plasma of different individuals, as well as replacing plasma with dextran. These measurements were complemented by clinical laboratory data and single-cell adhesion force measurements. Additionally, we followed theoretical modeling approaches. (3) Results: We show that the acanthocyte sedimentation rate (ASR) with a two-hour read-out is significantly prolonged in chorea-acanthocytosis and McLeod syndrome without overlap compared to the ESR of the controls. Mechanistically, through modern colloidal physics, we show that acanthocyte aggregation and plasma fibrinogen levels slow down the sedimentation. Moreover, the inverse of ASR correlates with the number of acanthocytes (R2=0.61, p=0.004). (4) Conclusions: The ASR/ESR is a clear, robust and easily obtainable diagnostic marker. Independently of NASs, we also regard this study as a hallmark of the physical view of erythrocyte sedimentation by describing anticoagulated blood in stasis as a percolating gel, allowing the application of colloidal physics theory.

Neurofilament light chain in serum is significantly increased in chorea-acanthocytosis.

INTRODUCTION: Chorea-acanthocytosis (ChAc) is a rare hereditary neurodegenerative disease, characterized by hyper- and hypokinetic movement disorders, peripheral neuropathy and acanthocytosis. Biomarkers are not established; possible candidates include neurofilament reflecting neuroaxonal damage. METHODS: We studied serum neurofilament light chain (sNfL) of six ChAc patients compared to two healthy control cohorts (A, six age/sex matched and B, historical cohort of 59 healthy adult subjects) and in two patients with the very similar condition of McLeod syndrome (MLS), the second core syndrome of neuroacanthocytosis. sNfL was quantified using single-molecule array analysis. RESULTS: sNfL concentration was significantly higher in the ChAc cohort (18.73 pg/ml; IQR 15.65-27.70) compared to both healthy control cohorts (A, 7.37 pg/ml; IQR 5.60-9.05; B, 3.10 pg/ml; IQR 2.43-3.98). In MLS patients, a similar sNfL increase was observed. CONCLUSIONS: sNfL is significantly increased in ChAc and MLS and seems to reflect neuroaxonal damage in the peripheral as well as the central nervous system.

McLeod syndrome: Five new pedigrees with novel mutations.

OBJECTIVE: To present five new McLeod Syndrome (MLS) pedigrees with novel XK gene mutations, review the literature of this disorder, and discuss the typical and atypical clinical features noted with these new mutations. METHODS: This is a multi-center retrospective review of five MLS cases with novel gene mutations. Genotypic and phenotypic information has been obtained from each center. RESULTS: Five novel mutations are reported in this Case series. New clinical findings include prolonged asymptomatic elevated creatine kinase (CK) levels, vocal tics, presence of obstructive sleep apnea (OSA), and one patient of Vietnamese ethnicity. CONCLUSIONS: We expand on the clinical and genetic spectrum of MLS demonstrating the clinical variability of MLS.

Current state of knowledge in Chorea-Acanthocytosis as core Neuroacanthocytosis syndrome.

Neuroacanthocytosis (NA) syndromes are a group of rare diseases characterized by neurological disorders and misshaped spiky red blood cells (acanthocytes) including Chorea-Acanthocytosis (ChAc), McLeod syndrome (MLS), Huntington disease-like 2 (HDL 2), pantothenate kinase-associated neurodegeneration (PKAN), abeta- and hypobetalipoproteinemia and aceruloplasminemia. This clinically and genetically heterogeneous group of diseases shares main clinical features presenting most often as a hyperkinetic movement disorder. Even though these are long noted disease conditions, we still know only little on the underlying disease mechanisms. The current review focuses upon ChAc as the core entity of NA syndromes caused by mutations in the VPS13A gene. The support of patient organizations and the ERA-NET initiative yielded to different multidisciplinary efforts with significant progress on our understanding of ChAc. Disturbances in two pathways are currently considered to be significantly involved in the pathophysiology of ChAc, namely elevated Lyn kinase phosphorylation and decreased signaling via Phosphoinositide 3-kinase (PI3K). These recent developments may reveal potential drugable targets for causative therapies of ChAc.

Drug-induced endovesiculation of erythrocytes is modulated by the dynamics in the cytoskeleton/membrane interaction.

Recent studies on erythrocyte membrane fluctuations revealed that the erythrocyte cytoskeleton actively modulates its membrane association thereby regulating crucial membrane properties. Cationic amphiphilic drugs like chlorpromazine are known to induce a cup-like cell shape and vesicle formation into the cell interior, effectors of this process, however, are largely unknown. Using flow cytometry, this study explored conditions that influence endovesiculation induced by chlorpromazine. We found that inhibitors of membrane fluctuations, like ATP depletion, vanadate or fluoride, also inhibited endovesiculation whereas activation of PKC, known to decrease cytoskeleton association and increase membrane fluctuations, also enhanced endovesicle formation. This indicates that endovesicle formation and membrane fluctuations are modulated by the same cytoskeleton-regulated membrane properties. Further, acanthocytic erythrocytes of chorea acanthocytosis (ChAc) patients that lack the VPS13A/chorein protein - likely a crucial organizer at the erythrocyte cytoskeleton/membrane interface - showed a strong decrease in chlorpromazine-induced endovesiculation. The responses of ChAc erythrocytes to effectors of endovesiculation were similar to that of control erythrocytes, yet at drastically reduced levels. This suggests a more rigid and less dynamic interaction at the membrane-cytoskeleton interphase of ChAc erythrocytes.

Phenotypic abnormalities in a chorea-acanthocytosis mouse model are modulated by strain background.

Chorea-acanthocytosis (ChAc) is an autosomal recessive hereditary disease characterized by neurodegeneration in the striatum and acanthocytosis that is caused by mutations in the VPS13A gene. We previously produced a ChAc model mice encoding a human disease mutation with deletion of exons 60-61 in the VPS13A gene. The behavioral and pathological phenotypes of the model mice varied a good deal from individual to individual, indicating that differences between individuals may be caused by the content of a genetic hybrid 129/Sv and C57BL/6J strain background. To establish the effect of the genetic background on phenotype, we backcrossed the ChAc-model mice to different inbred strains: C57BL/6J and 129S6/Sv. Although no significant difference between ChAc-mutant mice and wild-type mice on the C57BL/6J background was observed, the ChAc-mutant mice on the 129S6/Sv showed abnormal motor function and behavior. Furthermore, we produced ChAc-mutant mice on two different inbred strains: BALB/c and FVB. Significant reduction in weight was observed in ChAc mutant mice on the FVB and 129S6 backgrounds. We found a marked increase in the osmotic fragility of red blood cells in the ChAc mutant mice backcrossed to 129S6/Sv and FVB. The phenotypes varied according to strain, with ChAc mutant mice on the FVB and 129S6 backgrounds showing remarkably abnormal motor function and behavior. These results indicate that there are modifying genetic factors of ChAc symptoms.

Neurodegeneration in the elderly - When the blood type matters: An overview of the McLeod syndrome with focus on hematological features.

Multisystem deterioration occurs mainly in older individuals and may be related to physiological tissue degeneration. However, genetic predisposition may be unmasked by inappropriate functional and structural system deficiencies. McLeod syndrome (MLS) is a rare, multisystem disease which is X-chromosomal inherited and belongs to the neuroacanthocytosis syndromes (NAS). The main clinical manifestations contain progressive neuro-psychiatric and cognitive deterioration, choreatic movement disorder, as well as myopathy, sensory motor axonal neuropathy and cardiomyopathy. In addition, MLS patients have red blood cell abnormalities including immune-hematological, morphological and functional impairments of red blood cells. In large deletions, contiguous gene syndrome may arise, including Duchenne muscular dystrophia, cellular immunodeficiency or retinitis pigmentosa. Hematological abnormalities such as blood group abnormalities in Kell- and XK blood group system, formation of anti-public red blood cell alloantibodies, acanthocytosis and elevated creatinine phosphokinase may precede clinical disease manifestation for decades and provide tools for early diagnosis. Patients with unexplained neuro-muscular deterioration and/or neuro-psychological pathologies accompanied with hematological abnormalities should be investigated for MLS.

Chorein sensitivity of cytoskeletal organization and degranulation of platelets.

Chorea-acanthocytosis (ChAc), a lethal disease caused by defective chorein, is characterized by neurodegeneration and erythrocyte acanthocytosis. The functional significance of chorein in other cell types remained ill-defined. The present study revealed chorein expression in blood platelets. As compared to platelets from healthy volunteers, platelets from patients with ChAc displayed a 47% increased globular/filamentous actin ratio, indicating actin depolymerization. Moreover, phosphoinositide-3-kinase subunit p85 phosphorylation, p21 protein-activated kinase (PAK1) phosphorylation, as well as vesicle-associated membrane protein 8 (VAMP8) expression were significantly reduced in platelets from patients with ChAc (by 17, 22, and 39%, respectively) and in megakaryocytic (MEG-01) cells following chorein silencing (by 16, 54, and 11%, respectively). Activation-induced platelet secretion from dense granules (ATP release) and α granules (P-selectin exposure) were significantly less (by 55% after stimulation with 1 µg/ml CRP and by 33% after stimulation with 5 µM TRAP, respectively) in ChAc platelets than in control platelets. Furthermore, platelet aggregation following stimulation with different platelet agonists was significantly impaired. These observations reveal a completely novel function of chorein, i.e., regulation of secretion and aggregation of blood platelets.

[Neuroacanthocytosis: a diagnosis that should be considered]. / Neuroacantheocytoses: un diagnostic à ne pas méconnaître.

BACKGROUND: Neuroacanthocythosis regroup heterogeneous neurodegenerative diseases. These conditions share neurological, hematological and even systemic features. In spite of the genetic progress, their pathogenesis is still unknown. AIM: To report a new case of neuroacanthocythosis CASE REPORT: A 37-year-old woman was admitted for orofacial choreatic movement disorder. These movements were associated to dysarthria, lip and tongue mutilation, areflexia and raised plasma creatine kinase level. Examination of blood smear reveled 10% of acanthocytosis. Neuro-acanthocytosis diagnosis, precisely choreaacanthocytosis, was done. CONCLUSION: Neuro-acanthocytosis should be considered in any movement disorder in order to attempt a genetic counseling.

The first case report of neuroacanthocytosis in Thailand: utilization of a peripheral blood smear technique for detecting acanthocytes.

BACKGROUND: Neuroacanthocytosis (NA) is a heterogeneous group of hereditary syndromes characterized by the association of neurological abnormalities with acanthocytosis. Among those, chorea-acanthocytosis (ChAc) is the most frequent form, manifested by predominant orofacial dyskinesias associated with marked dysarthria and dysphagia. PURPOSE: To describe the first known case of ChAc in Thailand. METHODS AND RESULTS: A 40-year-old man presented with "core features" of NA which led to a high level of suspicion of this syndrome. An initial dry blood smear did not reveal acanthocytes but by utilizing diluted blood combined with a wet blood smear, which is accepted as the clinical gold standard when combined with an examination, acanthocytes were detected. CONCLUSION: Diagnosis of NA is possible without molecular diagnostics by relying on a high degree of clinical suspicion of characteristic clinical features and a standardized wet blood smear method of peripheral blood examination for acanthocytes.