Affiliations: [a] CHRU de Tours, Tours, France | [b] Université François Rabelais de Tours, Tours, France | [c] INSERM, U930, Imagerie et cerveau, Tours, France
Correspondence:
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Correspondence to: Emilie Beaufils, MD, CHU Bretonneau, Centre Mémoire Ressources et Recherche, 2 Bd Tonnellé, 37044 Tours cedex 9, France. Tel.: +33 (0)2 34 37 89 52; E-mail: e.beaufils@chu-tours.fr.
Note: [1] These authors contributed equally.
Abstract: Posterior cortical atrophy (PCA) is characterized by progressive higher-order visuo-perceptual dysfunction and praxis declines. This syndrome is related to several underlying diseases, including Alzheimer's disease (AD), sometimes involving an amyloidogenic process. The aims of the study were to 1) define cerebrospinal fluid (CSF) biomarker profiles in PCA patients compared to AD patients and 2) explore the amyloidogenic process through the Aβ42/Aβ40 ratio in PCA patients to elucidate the underlying disease in vivo. CSF biomarker analysis (t-tau, p-tau, Aβ42, and Aβ42/Aβ40 ratio) and neuropsychological examination were performed in 22 PCA patients and compared with those of age-matched AD patients. Associated clinical neurological signs were investigated (e.g., extrapyramidal motor signs, myoclonus). CSF biomarker profiles did not differ significantly between the PCA and AD groups; 82% of patients with PCA fulfilled the biological criteria for typical AD with abnormal levels of the three markers and 18% of PCA patients presented atypical CSF profiles. All PCA patients with associated clinical neurological signs presented typical AD CSF profiles. The clinical presentations of these patients were similar to other PCA subjects. The Aβ42/Aβ40 ratio for all PCA patients, including those with atypical CSF profiles, was decreased. Most PCA syndromes were associated with CSF biomarkers suggestive of AD, even in cases with associated clinical neurological signs. The amyloidogenic process was confirmed by the decreased Aβ42/Aβ40 ratio for all patients. This analysis avoids misdiagnosis in the presence of physiologically high or low amyloid peptide production rates and provides information in vivo to improve understanding of the underlying disease in PCA.
