Ceren Tunca, Eylül Ece İşlek Camadan, Natalia Smolina, Robin J Palvadeau, Özgür Öztop Çakmak, Atay Vural, Andreas Traschütz, Filippo M Santorelli, Bernard Brais, Rebecca Schüle, Matthis Synofzik, A Nazlı Başak
Sacsin levels in PBMCs: A diagnostic assay for SACS variants in peripheral blood cells - A PROSPAX study.
Background: Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a common recessive ataxia that is still underdiagnosed worldwide. An easily accessible diagnostic biomarker might help to diagnostically confirm patients presenting SACS variants of unknown significance (VUS) or atypical phenotypes.
Objectives: To detect sacsin in peripheral blood mononuclear cells (PBMCs) and to validate its diagnostic biomarker quality to discriminate biallelic SACS patients (including patients with VUS and/or atypical phenotypes) against healthy controls, non-ARSACS spastic ataxia patients, and heterozygous SACS carriers.
Methods: Sacsin protein levels in PBMCs were assessed in patients versus controls and validated in skin-derived fibroblasts.
Results: Patients with biallelic SACS variants - including patients with VUS and/or atypical phenotypes - showed loss of sacsin in PBMCs, with discriminative performance against healthy, heterozygous, and non-ARSACS controls. This included all investigated SACS missense variants. Also, C-terminal variants escaping nonsense-mediated decay, while not differing from controls in expression level, showed lower molecular weight in this assay.
期刊介绍:
Movement Disorders publishes a variety of content types including Reviews, Viewpoints, Full Length Articles, Historical Reports, Brief Reports, and Letters. The journal considers original manuscripts on topics related to the diagnosis, therapeutics, pharmacology, biochemistry, physiology, etiology, genetics, and epidemiology of movement disorders. Appropriate topics include Parkinsonism, Chorea, Tremors, Dystonia, Myoclonus, Tics, Tardive Dyskinesia, Spasticity, and Ataxia.