Neuroimaging findings in infantile Pompe patients treated with enzyme replacement therapy

Abstract

Background: Recombinant human acid α-glucosidase (rhGAA) enzyme replacement therapy (ERT) has prolonged survival in infantile Pompe disease (IPD), but has unmasked central nervous system (CNS) changes.

Methods: Brain imaging, consisting of computed tomography (CT) and/or magnetic resonance imaging (MRI), was performed on 23 patients with IPD (17 CRIM-positive, 6 CRIM-negative) aged 2-38months. Most patients had baseline neuroimaging performed prior to the initiation of ERT. Follow-up neuroimaging was performed in eight.

Results: Sixteen patients (70%) had neuroimaging abnormalities consisting of ventricular enlargement (VE) and/or extra-axial cerebrospinal fluid accumulation (EACSF) at baseline, with delayed myelination in two. Follow-up neuroimaging (n=8) after 6-153months showed marked improvement, with normalization of VE and EACSF in seven patients. Two of three patients imaged after age 10years demonstrated white matter changes, with one noted to have a basilar artery aneurysm.

Conclusions: Mild abnormalities on brain imaging in untreated or newly treated patients with IPD tend to resolve with time, in conjunction with ERT. However, white matter changes are emerging as seen in Patients 1 and 3 which included abnormal periventricular white matter changes with subtle signal abnormalities in the basal ganglia and minimal, symmetric signal abnormalities involving the deep frontoparietal cerebral white matter, respectively. The role of neuroimaging as part of the clinical evaluation of IPD needs to be considered to assess for white matter changes and cerebral aneurysms.

Keywords: Acid maltase deficiency; Alglucosidase alfa; Blood-brain barrier; CT; Central nervous system; Enzyme replacement therapy; Glycogen storage disease type II; MRI; Neuroimaging; Neuromuscular diseases; Pompe disease; rhGAA.

Conflict of interest statement

Conflict of interest disclosures:

PSK has received research/grant support and honoraria from Genzyme Corporation and Amicus Therapeutics. PSK is a member of the Pompe and Gaucher Disease Registry Advisory Board for Genzyme Corporation. LDH has received research/grant support and honoraria from Genzyme, a Sanofi Company. LDH has also received a consultant fee for Wiley for role as Associate Editor of Muscle & Nerve. PM has received speaker honorarium from Genzyme as a participant in Genzyme’s Patient Speakers Bureau. ZBK, SP, SB, SA, RW, DE and DF do not have conflicts to disclose.

Copyright © 2017 Elsevier Inc. All rights reserved.

Figures

Figure 1

(A) Axial head CT in a 6.5-month-old male (Patient 7) at the level of the upper ventricles is notable for prominent bifrontal extra-axial CSF spaces and mild prominence of the lateral ventricles. (B) Axial T1-weighted brain MRI of the same patient at 13 months of age (6 months into ERT) shows normalization of bifrontal extra-axial spaces and lateral ventricles.

Figure 2

(A) Baseline axial T1-weighted brain MRI in a 9-month-old male (Patient 5) demonstrates mild enlargement of the lateral ventricles and mild prominence of the bifrontal extra-axial CSF spaces in addition to incomplete myelination of the genu of the corpus collosum and relatively reduced subcortical white matter; (B) corresponding baseline T2-weighted image shows decreased white matter and mild delay in myelination of the genu of the corpus callosum (arrows). (C) Follow-up axial T1-weighted brain MRI of the same child obtained at 50 months of age (47 months into ERT) demonstrates normalization of the ventricles and extra-axial CSF spaces. There was significant interval progression of myelination with only residual delayed myelination seen on the follow-up study.

Figure 3

Axial T2-weighted brain MRI in a 158-month-old (13.2 years) male (Patient 1) showing diffuse increased signal intensity periventricular white matter changes.