Orphanet Journal of Rare Diseases

A quantitative assessment of the evolution of cerebellar syndrome in children with phosphomannomutase-deficiency (PMM2-CDG)

Natalia Lourdes Serrano,
Victor De Diego,
Daniel Cuadras,
Antonio F. Martinez Monseny,
Ramón Velázquez-Fragua,
Laura López,
Ana Felipe,
Luis G. Gutiérrez-Solana,
Alfons Macaya,
Belén Pérez-Dueñas,
Mercedes SerranoEmail author View ORCID ID profile and
CDG Spanish-Consortium

Orphanet Journal of Rare Diseases201712:155

https://doi.org/10.1186/s13023-017-0707-0

Received: 22 March 2017

Accepted: 6 September 2017

Published: 15 September 2017

Abstract

Background

We aim to delineate the progression of cerebellar syndrome in children with phosphomannomutase-deficiency (PMM2-CDG) using the International Cooperative Ataxia Rating Scale (ICARS). We sought correlation between cerebellar volumetry and clinical situation. We prospectively evaluated PMM2-CDG patients aged from 5 to 18 years through ICARS at two different time points set apart by at least 20 months. We reviewed available MRIs and performed volumetric analysis when it was possible.

Results

From the eligible 24, four patients were excluded due to severe mental disability (n = 2) and supratentorial lesions (n = 2). Two different ICARS evaluations separated by more than 20 months were available for 14 patients showing an improvement in the cerebellar syndrome: ICARS1: 35.71 versus ICARS2: 30.07 (p < 0.001). When we considered time, we saw an improvement of 2.64 points in the ICARS per year with an SD of 1.97 points (p < 0.001). The ICARS subscales results improved with time, reaching statistical significance in “Posture and gait” (p < 0.001), “Kinetic functions” (p = 0.04) and “Speech abnormalities” (p = 0.045). We found a negative correlation between the ICARS results and total cerebellar volume (r = −0.9, p = 0.037) in a group of five patients with available volumetric study, meaning that the higher the ICARS score, the more severe was the cerebellar atrophy.

Conclusions

Our study shows a stabilization or mild improvement in the cerebellar functions of paediatric PMM2-CDG patients despite cerebellar volume loss. ICARS is a valid scale to quantify the evolution of cerebellar syndrome in PMM2-CDG patients. The availability of ICARS and other reliable and sensitive follow-up tools may prove essential for the evaluation of potential therapies.