AUTHOR=Hernández Carolina A. , Peikert Kevin , Qiao Min , Darras Alexis , de Wilde Jonathan R. A. , Bos Jennifer , Leibowitz Maya , Galea Ian , Wagner Christian , Rab Minke A. E. , Walker Ruth H. , Hermann Andreas , van Beers Eduard J. , van Wijk Richard , Kaestner Lars 

TITLE=Osmotic gradient ektacytometry – a novel diagnostic approach for neuroacanthocytosis syndromes

JOURNAL=Frontiers in Neuroscience

VOLUME=18

YEAR=2024

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2024.1406969

DOI=10.3389/fnins.2024.1406969

ISSN=1662-453X

ABSTRACT=<sec id="sec1"><title>Introduction</title><p>The unique red blood cell (RBC) properties that characterize the rare neuroacanthocytosis syndromes (NAS) have prompted the exploration of osmotic gradient ektacytometry (Osmoscan) as a diagnostic tool for these disorders. In this exploratory study, we assessed if Osmoscans can discriminate NAS from other neurodegenerative diseases.</p></sec><sec id="sec2"><title>Methods</title><p>A comprehensive assessment was conducted using Osmoscan on a diverse group of patients, including healthy controls (<italic>n</italic> = 9), neuroacanthocytosis syndrome patients (<italic>n</italic> = 6, 2 VPS13A and 4 XK disease), Parkinson’s disease patients (<italic>n</italic> = 6), Huntington’s disease patients (n = 5), and amyotrophic lateral sclerosis patients (<italic>n</italic> = 4). Concurrently, we collected and analyzed RBC indices and patients’ characteristics.</p></sec><sec id="sec3"><title>Results</title><p>Statistically significant changes were observed in NAS patients compared to healthy controls and other conditions, specifically in osmolality at minimal elongation index (O<sub>min</sub>), maximal elongation index (EI<sub>max</sub>), the osmolality at half maximal elongation index in the hyperosmotic part of the curve (O<sub>hyper</sub>), and the width of the curve close to the osmolality at maximal elongation index (O<sub>max</sub>-width).</p></sec><sec id="sec4"><title>Discussion</title><p>This study represents an initial exploration of RBC properties from NAS patients using osmotic gradient ektacytometry. While specific parameters exhibited differences, only O<sub>hyper</sub> and O<sub>max</sub>-width yielded 100% specificity for other neurodegenerative diseases. Moreover, unique correlations between Osmoscan parameters and RBC indices in NAS versus controls were identified, such as osmolality at maximal elongation index (O<sub>max</sub>) vs. mean cellular hemoglobin content (MCH) and minimal elongation index (EI<sub>min</sub>) vs. red blood cell distribution width (RDW). Given the limited sample size, further studies are essential to establish diagnostic guidelines based on these findings.</p></sec>