Clinical and Electrodiagnostic Characterization of Pediatric Triple A Syndrome: A Cohort of 17 Patients.

INTRODUCTION/AIMS: Triple A syndrome is an autosomal recessive disorder characterized by alacrima, achalasia, and adrenal insufficiency. Neurological involvement is common, but its electrodiagnostic (EDX) patterns are varied. The resulting phenotype, often marked by spasticity, can lead to diagnostic confusion with other motor neuron disorders. We aimed to define the neurological and EDX spectrum in a pediatric cohort and clarify their diagnostic relevance.

METHODS: This was a cross-sectional study of 17 pediatric patients with genetically confirmed triple A syndrome. All patients underwent neurological examinations by a pediatric neurologist. EDX data, including nerve conduction studies (NCS) and concentric needle electromyography (EMG) from 14 patients, were systematically analyzed for motor and sensory involvement.

RESULTS: Neurological examinations revealed upper motor neuron (UMN) signs, including hyperreflexia, extensor plantar responses, lower limb hypertonia, and a spastic gait pattern, including toe walking and early heel rise. Some patients showed peripheral neuropathy signs, including pes cavus and distal muscle atrophy. EDX studies indicated a predominantly distal, axonal motor polyneuropathy with infrequent sensory involvement. Needle EMG demonstrated chronic neurogenic changes in distal muscles; however, active denervation, such as fibrillation potentials and fasciculation potentials, were observed in only one patient.

DISCUSSION: The presence of spastic paraparesis and hyperreflexia may clinically resemble hereditary spastic paraplegia, while distal motor involvement may raise consideration of motor neuron disorders. The predominance of chronic neurogenic changes and the relative infrequency of active denervation on needle EMG are key diagnostic features that help differentiate Triple A syndrome from classical motor neuron diseases.