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Keywords:

  • amyloid beta protein;
  • cerebrospinal fluid;
  • myotonic dystrophy type 1;
  • tau protein

Background and purpose

The aim of the present study was to analyze cerebrospinal fluid (CSF) levels of total tau (T-tau), phosphorylated tau (P-tau) and the 42-amino-acid form of β-amyloid (Aβ42) in patients with myotonic dystrophy type 1 (DM1), and their possible correlations with cognitive and behavioral manifestations in these patients.

Methods

Lumbar puncture was performed in 74 patients with DM1 [27 with the childhood/juvenile form (jDM1) and 47 with the adult form (aDM1) of the disease] and 26 control subjects who were subjected to orthopedic surgery. Sandwich ELISA was used for measuring the levels of T-tau, P-tau and Aβ42.

Results

The CSF level of Aβ42 was at its lowest in patients with jDM1 and at its highest in controls (< 0.05). A tendency of T-tau and P-tau to increase was greater in aDM1 patients than in jDM1 patients and controls (P > 0.05). In both jDM1 and aDM1 patients, significant correlations were found between Aβ42 and T-tau (rho = 0.81 and rho = 0.67, respectively, < 0.01), as well as between Aβ42 and P-tau (rho = 0.87 and rho = 0.67, respectively, < 0.01). The Aβ42/P-tau ratio decreased with age in aDM1 patients (rho = −0.30, < 0.05). Only the level of Aβ42 in the CSF of jDM1 patients was correlated with the size of the CTG expansion (rho = −0.53, < 0.05). Only a few correlations were observed between levels of biomarkers and neuropsychological testing.

Conclusion

The CSF level of Aβ42 was decreased in patients with jDM1, whilst the Aβ42/P-tau ratio was decreased in aDM1 patients. Positive correlations between Aβ42, T-tau and P-tau were observed in both forms of disease. Further studies with larger cohorts of DM1 patients are necessary.