Observational study including 13 PMM2-CDG patients and 21 control subjects. Ethical permission and informed consents were obtained. Three independent child neurologists rated PMM2-CDG patients with the ICARS, whereas the NPCRS was administered by a single observer. All patients underwent brain MRI and midsaggital vermis relative diameter was obtained. Psychometric evaluations were available in 6 patients. Mann-Whitney U test was used to compare ICARS between patients and controls. To evaluate inter-observer agreement in patients' ICARS, intraclass correlation coefficients (ICC) were calculated. ICARS Internal consistency was evaluated using Cronbach's alpha. Spearman's rank correlation coefficient test was used to correlate ICARS with NPCRS, midsaggital vermis relative diameter, and intelligence quotients (IQ).
ICARS and ICARS subscores differed between patients and controls (p<0.001). The ICCs for interobserver agreement of ICARS was “almost perfect” (ICC=0.99), with a “good” internal reliability (Cronbach's alpha = 0.72). ICARS was significantly correlated with total NPCRS (rs 0.90, p <0.001). However, there was no agreement regarding categories of severity. Regarding neuroimaging, an inverse correlation between midsagittal vermis relative diameter and ICARS was found (rs –0.85, p=0.003). There was a negative correlation between ICARS and IQ (rs –0.94, p=0.005). All correlations remained significant when using corrected-by-age ICARS value.
a40">ICARS is a reliable instrument for assessment of PMM2-CDG patients, without significant inter-rater variability. Despite limited sample size, results hint a good correlation between functional cerebellar assessment, IQ and neuroimaging data. ICARS may represent a valuable tool to evaluate therapeutic interventions on cerebellum dysfunction in PMM2-CDG patients.