Laryngeal Abductor Paralysis With Cerebellar Ataxia And Motor Neuropathy

Clinical Features

Barbieri et al. (2001) described 2 brothers who presented with late-onset cerebellar ataxia and severe dysphonia. Brain MRI showed vermian and hemispheric cerebellar atrophy. Both brothers displayed laryngeal abductor paralysis on laryngoscopy. Neurophysiologic studies showed a pure motor neuropathy. The index case was a 66-year-old man who had hoarseness and nocturnal laryngeal stridor for 20 years. He had developed unsteady gait at the age of 52 years. He also had occasional urinary incontinence and dysphagia. All symptoms were slowly progressive. In addition to characteristic cerebellar signs, there were diffuse limb fasciculations with mild distal muscular wasting. His 60-year-old brother had a 20-year history of dysphonia and nocturnal respiratory distress, and a 3-year history of unsteady gait. Cognition, muscle tone, and sensory examination were normal in both brothers. Molecular genetic testing for the most frequent spinocerebellar ataxias and the commonly encountered pathogenic mitochondrial DNA mutations were negative, and deletions of exons 7 and 8 of the SMN1 gene (600354) and the related NAIP gene (600355) were also excluded by PCR-restriction fragment length polymorphism. Barbieri et al. (2001) suggested that the brothers had a distinct disorder that is most likely transmitted as an autosomal recessive. They distinguished the disorder from laryngeal abductor paralysis, or Gerhardt syndrome (150260), which appears to be inherited as an autosomal dominant with variable expression but may also be X-linked (308850). The authors also noted that bilateral paralysis of the abductor laryngeal muscles is sometimes associated with a form of hereditary motor and sensory neuropathy (606071).