Young infants with PMP22 duplication can have minor nerve conduction study abnormalities
Jean-Baptiste Davion1, François Cassim2, Yann Péréon3
1Centre de référence des Maladies Neuromusculaires, CHU Lille, Lille, France; Service de Neurologie pédiatrique, CHU Lille, France.
Insights
Normal nerve conduction studies (NCS) can occur in infants with Charcot-Marie-Tooth disease type 1A (CMT1A). Delayed electrodiagnostic testing (EDX) abnormalities in CMT1A patients may impact early diagnosis and clinical trials.
Area of Science:
- Neurology
- Genetics
- Biochemistry
Background:
- Charcot-Marie-Tooth disease type 1A (CMT1A) is a genetic peripheral neuropathy caused by PMP22 gene duplication.
- Electrodiagnostic testing (EDX) in CMT1A typically shows demyelination, including slowed nerve conduction velocities and prolonged distal latencies.
Observation:
- Abnormalities on EDX are often less pronounced in infants under two years old.
- The possibility of normal nerve conduction studies (NCS) in infants under one year with CMT1A has been debated.
Findings:
- This study reports three infants diagnosed with CMT1A who presented with normal or near-normal NCS.
- These findings suggest that EDX abnormalities in CMT1A may not be apparent at birth or in early infancy.
Implications:
- Delayed presentation of EDX abnormalities in CMT1A can complicate early diagnosis in infants.
- These findings are crucial for designing and interpreting results from clinical trials targeting early-stage CMT1A.
Abstract:
Charcot-Marie-Tooth disease type 1A (CMT1A) is related to PMP22 gene duplication. It is characterized at electrodiagnostic testing (EDX) by diffuse homogeneous signs of demyelination, such as velocity slowing and prolonged distal latencies. These abnormalities are less pronounced in infants under two years old, and the possibility of normal nerve conduction studies (NCS) in infants with CMT1A under one year of age has been questioned. We report three infants who displayed normal or almost normal NCS. EDX abnormalities in CMT1A patients may therefore appear late during development. This may affect early EDX diagnosis in infants and should be considered for upcoming clinical trials.
