Sensory neuronopathies, diagnostic criteria and causes

Area of Science:

• Neurology
• Immunology
• Genetics

Background:

• Sensory neuronopathies (SNN) encompass diverse mechanisms including paraneoplastic, dysimmune, toxic, viral, and genetic factors, with a significant portion historically remaining idiopathic.
• Recent advancements in identifying novel antibodies and genetic mutations have begun to elucidate the causes of previously unexplained SNN cases.

Purpose of the Study:

• To update the diagnostic strategy for sensory neuronopathies (SNN).
• To incorporate newly identified antibodies and genetic factors into the diagnostic approach for SNN.

Main Methods:

• Review of recent findings on antibodies (anti-FGFR3, anti-AGO) and genetic mutations (RFC1 gene) associated with SNN.
• Analysis of diagnostic criteria for paraneoplastic SNN and differentiation from other neuropathies.

Main Results:

• Anti-FGFR3 and anti-AGO antibodies, while not exclusive to SNN, serve as key markers for underlying dysimmune contexts in a substantial proportion of patients.
• A biallelic expansion in the RFC1 gene is identified as the cause of cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS), potentially accounting for one-third of idiopathic sensory neuropathies.
• Updated diagnostic criteria for paraneoplastic SNN have been established.

Conclusions:

• The diagnostic strategy for SNN must integrate new antibody and genetic discoveries to improve etiological diagnosis.
• These advancements are critical for distinguishing SNN from other neuropathies and guiding appropriate management.