Quantitative whole-body magnetic resonance imaging in children with Pompe disease: Clinical tools to evaluate severity of muscle disease

JIMD Rep 2020 Oct 14;57(1):94-101. doi: 10.1002/jmd2.12174. eCollection 2021 Jan.

PMID: 33473345

Samuela A Fernandes, Aleena A Khan, Tracy Boggs

Highlights: This article reports a measure of muscle fat infiltration in children with infantile and pediatric late-onset Pompe disease (IPD and LOPD, respectively) to better understand the extent of muscle involvement.

Abstract

Objective: There has been an increase in survival in patients with Pompe disease after the introduction of enzyme replacement therapy (ERT) with alglucosidase alfa. Characterizing and quantifying the disease burden in these patients is critical. To further understand the level of muscle involvement, we present a measure of muscle fat infiltration in children with infantile and pediatric late-onset Pompe disease (IPD and LOPD, respectively).

Methods: Eleven children with Pompe disease (five IPD and six LOPD) between the ages of 7 and 17 years old underwent whole-body magnetic resonance imaging (WBMRI), muscle strength testing using the modified Medical Research Council (mMRC) scale, functional assessment using gait, stairs, gowers, and chair (GSGC), and urine glucose tetrasaccharide (Glc4) testing. Using proton density fat fraction (PDFF), the intramuscular fat detected on WBMRI was measured and correlated to suitable muscle strength and functional tests, as well as urine Glc4.

Results: Despite being younger, IPD patients had higher mean PDFF values than LOPD patients (11.61% vs 8.52%). The PDFF and the GSGC assessment had a significant connection (r =.9273, P =.0003). PDFF and mMRC (r = -.667, P =.0831) and PDFF and urine Glc4 (r =.6121, P =.0667) had a moderate connection. For patients with LOPD, the anterior tibialis was in the top quartile of muscle involvement.

Conclusion: Previously, only physical therapy exams were utilized to track disease progression. We demonstrate the clinical efficacy of WBMRI in assessing muscle involvement in children with Pompe disease, particularly the novel involvement of the anterior tibialis in children with LOPD, in order to better characterize baseline muscle burden and disease progression in children treated with ERT.

Keywords: Pompe, infantile Pompe disease, late‐onset Pompe disease, muscle function testing, muscle strength testing, newborn screening, whole‐body magnetic resonance imaging