Late infantile neuroaxonal dystrophy. An unusual case with predominantly myoclonic-epileptic symptomatology

Area of Science:

• Neurology
• Neuroscience
• Genetics

Background:

• Infantile neuroaxonal dystrophy (INAD) is a rare, inherited neurodegenerative disorder.
• Typical INAD presents in early childhood with motor and cognitive regression.
• Late-onset forms of INAD are less common and may present with atypical symptoms.

Purpose of the Study:

• To describe a case of late-onset infantile neuroaxonal dystrophy (INAD).
• To highlight the diagnostic challenges posed by its clinical presentation.
• To emphasize the importance of considering INAD in the differential diagnosis of progressive myoclonus epilepsies.

Main Methods:

• Case report of a 13-year-old girl with a 8-year history of neurological decline.
• Clinical assessment including neurological examination and observation of symptoms.
• Histopathological examination of the central nervous system (CNS).

Main Results:

• The patient exhibited a protracted course with cerebellar deficit, intellectual impairment, and progressive myoclonic seizures.
• Histology confirmed diffuse neuroaxonal dystrophy, spongy degeneration, cerebellar atrophy, and demyelination consistent with INAD.
• Clinical presentation mimicked progressive myoclonus epilepsies, differing from typical Seitelberger or Hallervorden-Spatz disease.

Conclusions:

• Late-onset INAD can present with a clinical phenotype overlapping with progressive myoclonus epilepsies.
• Histopathological findings are crucial for diagnosing INAD, even with atypical clinical features.
• INAD should be considered in the differential diagnosis of rare neurological disorders with myoclonic-epileptic symptoms.