Introduction: Noonan Syndrome (NS) is caused by a mutation of genes, leading to hyperactivation
of the Ras-pathway. Recent in vitro studies demonstrated a Long Term Potentiation
(LTP) impairment caused by RAS-pathway hyperactivity.
Methods: In this study 8 patients with Noonan-Syndrome (mean 26.25±11.25 years, 5 female,
3 male) and an age and gender matched control group (mean 25.13±3.44 years, 5 female,
3 male) were investigated using paired associated stimulation (PAS). Changes in MEP
amplitude were investigated before, immediately after (post 1), 30 (post2) and 60
(post 3) minutes after PAS.
Results: We demonstrated that MEP amplitudes of healthy controls did increase significantly
from 1.03±0.18 to 1.81±0.61 mV (Post 3: p=0.006, paired t test), which was not seen
in patients with Noonan-Syndrome 0.88±0.1 to 1.2±0.49 mV and that there was a significant
difference between both groups at this point in time (p=0.044, unpaired t test).
Discussion: In conclusion, synaptic plasticity in patients with NS is impaired which may be caused
by constitutive activity of the Ras pathway.
