An observational study in Pompe Disease, sponsored by IRCCS National Neurological Institute "C. Mondino" Foundation. Recruiting at 1 site in Italy. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-24.
Sponsored by IRCCS National Neurological Institute "C. Mondino" Foundation · Observational
Pompe disease is traditionally considered a lysosomal myopathy. However, increasing experimental and clinical evidence suggests involvement of the entire motor unit, including motor neurons, peripheral nerves, neuromuscular junctions, and skeletal muscle. Respiratory impairment is a major cause of morbidity and mortality, and diaphragm dysfunction is frequently observed.
Clinical observations at IRCCS Fondazione Mondino have highlighted neurophysiological abnormalities of the phrenic nerve and diaphragm in patients with Pompe disease and respiratory involvement, sometimes occurring even in the absence of clinically significant limb muscle weakness. These findings suggest that respiratory motor unit dysfunction may represent an important component of the disease phenotype.
This observational study aims to systematically characterize phrenic nerve conduction parameters and diaphragm electromyographic findings in adult patients with genetically confirmed Pompe disease and in patients with unexplained respiratory failure. Retrospective and prospective clinical, neurophysiological, and respiratory data collected during routine clinical care will be analyzed to explore whether phrenic nerve and diaphragm abnormalities may serve as markers of respiratory motor unit involvement in Pompe disease.
This is a non-interventional observational study with a mixed retrospective and prospective cohort design. No experimental treatments, additional diagnostic procedures, or study-specific interventions are introduced. All data derive exclusively from routine clinical evaluations performed as part of standard patient care. Two main populations are included: 1) Adult patients with genetically confirmed Pompe disease undergoing routine neurophysiological and respiratory assessments; 2) Patients with restrictive respiratory failure or unexplained hypoventilation who previously underwent phrenic nerve conduction studies and/or diaphragm electromyography as part of clinical workup, identified retrospectively. The retrospective component consists of systematic review of phrenic nerve conduction studies and diaphragm electromyography performed over previous years in patients with suspected neuromuscular respiratory failure. The prospective component involves standardized collection of neurophysiological and respiratory data obtained during routine follow-up of patients with confirmed Pompe disease.
Neurophysiological assessments include bilateral phrenic nerve motor conduction studies and evaluation of peripheral nerves and limb muscles. Diaphragm needle electromyography is performed only when clinically indicated. Respiratory evaluations include spirometry with forced vital capacity in seated and supine positions, maximal inspiratory and expiratory pressures (MIP/MEP), and, when clinically required, overnight ventilation studies.
The primary outcome is the characterization of phrenic nerve conduction parameters, including motor latency, compound muscle action potential amplitude, and presence or absence of diaphragmatic responses. Secondary outcomes include diaphragm electromyographic patterns, comparison between phrenic nerve and other peripheral nerves, and correlations between neurophysiological parameters and respiratory function.
Data are collected retrospectively from medical records and prospectively during routine clinical visits, pseudonymized, and analyzed descriptively and exploratorily. The study aims to improve characterization of respiratory motor unit involvement in Pompe disease and to evaluate the potential diagnostic contribution of phrenic nerve and diaphragm electrophysiology in patients with unexplained respiratory failure.
162 studies on the registry are indexed under Glycogen Storage Disease Type II; 34 are open to participants now.
This study's planned enrollment of 20 is below the median of 50 across 64 observational studies indexed under Glycogen Storage Disease Type II.
Browse Glycogen Storage Disease Type II studies →IRCCS National Neurological Institute "C. Mondino" Foundation is the lead sponsor of 57 studies on the registry; 20 are open to participants now.
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Approximately 20 adult patients with genetically confirmed Pompe disease are expected to be prospectively included. In addition, a retrospective review of approximately 150 previously performed phrenic nerve conduction studies and diaphragm electromyography examinations in patients with unexplained respiratory failure will be conducted. The prospective enrollment refers exclusively to newly evaluated Pompe disease patients, while the retrospective component is based on existing clinical records and neurophysiological data
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Age ≥ 18 years.
For the prospective cohort:
For the retrospective cohort:
Exclusion Criteria:
- Age \< 18 years.
For the prospective cohort:
For the retrospective cohort:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Motor latency (ms)
Phrenic nerve conduction parameter measured by bilateral nerve conduction studies
Time frame: Baseline (at first available assessment, retrospective or prospective)
Compound muscle action potential (CMAP) amplitude (millivolts)
Phrenic nerve conduction parameter assessed bilaterally by nerve conduction studies
Time frame: Baseline (at first available assessment, retrospective or prospective)
Presence or absence of diaphragmatic responses
Phrenic nerve conduction parameter assessed bilaterally
Time frame: Baseline (at first available assessment, retrospective or prospective)
Neurogenic pattern
Diaphragm electromyography pattern assessed when clinically indicated
Time frame: Baseline (at time of clinical assessment when EMG is performed)
Myopathic pattern
Diaphragm electromyography pattern assessed when clinically indicated
Time frame: Baseline (at time of clinical assessment when EMG is performed)
Mixed pattern
Diaphragm electromyography pattern assessed when clinically indicated
Time frame: Baseline (at time of clinical assessment when EMG is performed)
Normal pattern
Diaphragm electromyography pattern assessed when clinically indicated
Time frame: Baseline (at time of clinical assessment when EMG is performed)
Plan to share: No
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Glycogen Storage Disease Type II →
IRCCS National Neurological Institute "C. Mondino" Foundation