A Ten-year Delayed Diagnosis of Hereditary Spastic Paraplegia Type-10: Key Clinical, Electrodiagnostic, and Genetic Findings
Estefania Rojo - Bustamante1, César Forero Botero2, Armando Dumar - Riaño3, Ángela Gómez - Mazuera4
1Neurology, Universidad El Bosque, 2Neurology/Neurophysiology, Fundación Santa Fe de Bogotá Teaching Hospital, 3Neurology/Neurophysiology, Fundación Santa Fe de Bogotá Teaching Hospital, Hospital San José Infantil, 4Neurology/Neurophysiology, Fundación Santa Fe de Bogotá Teaching Hospital, Universidad El Rosario
Objective:
Here we present the case of a nineteen-years-old male patient with neurodevelopmental delay, altered profound sensibility in four limbs, frequent falls, disturbed gait pattern, patellar hyperreflexia, bilateral pes cavus, and extensor plantar response, in whom an Autosomal Dominant Spastic paraplegia type-10 (SPG-10), was identified.
Background:
SPG-10 is a neurologic disorder with variable manifestations. It is mainly characterized by distal sensory impairment, although some patients can show axonal sensorimotor peripheral neuropathy and distal muscle atrophy resembling Charcot-Marie-Tooth disease type 2 (CMT-2).
Design/Methods:
After obtaining a detailed medical history and a thorough physical examination, follow-up electrodiagnostic studies, were performed. In light of the findings, an extended diagnostic workup,including genetic evaluation, was followed.
Results:
Electrodiagnostic: Nerve Conduction Velocities (NCVs). Motor: Median and ulnar nerves presented decreased NCVs with normal amplitudes and prolonged distal latencies in the median nerves. The tibial nerves showed decreased NCVs with very low amplitudes and unaffected distal latencies. The F waves in the ulnar nerves were normal, while the F waves and H reflexes were absent in the tibial nerves. Sensitive: Median, ulnar, and radial nerves exhibited decreased NCVs with prolonged peak latencies and low amplitudes in median and ulnar nerves. Electromyography: Explored musclesrevealed a neuropathic pattern with signs of chronic evolution given by decreased recruitment with polyphasic potentials, increased amplitudes, and durations. Genetics: Sequencing of the Mitofusin 2 (MFN2) gen did not identify pathogenic variants related to CMT-2. Whole exome sequencing detected the heterozygous pathogenic variant c.839G>A; p.(Arg280His) in the kinesin familymember 5A (KIF5A) gen.
Conclusions:
To our knowledge, this is the first case of SPG-10 identified in our country (Colombia). Peripheral nerve disorders are frequently misdiagnosed entities given the overlapping features of some phenotypes. Identifying patients with orphan disorders like SPG-10, is needed to develop the best possible treatments for people affected by these conditions.