The evolving spectrum of complex inherited neuropathies

Area of Science:

• Genetics
• Neurology
• Molecular Biology

Background:

• Inherited peripheral neuropathies are classified into those primarily affecting the nerves (e.g., Charcot-Marie-Tooth disease) and those as part of broader syndromes.
• Recent advancements have significantly increased the number of identified genes linked to complex neuropathy syndromes.

Purpose of the Study:

• To review emerging themes in complex inherited neuropathies.
• To provide a practical diagnostic approach for patients with peripheral neuropathy as a feature of a complex syndrome.
• To present an updated table of associated genes.

Main Methods:

• Literature review focusing on recent findings in complex neuropathy syndromes.
• Analysis of emerging genetic mechanisms, including repeat expansions and allele variations.
• Discussion of diagnostic challenges, such as allele loss in hematopoietic stem cells.

Main Results:

• An increasing number of complex neuropathies are linked to repeat expansion genetic disorders.
• Both recessive and dominant-negative alleles within the same gene can cause similar phenotypes.
• Selective allele loss from hematopoietic stem cells complicates genetic diagnosis using blood DNA.

Conclusions:

• A practical framework for investigating and diagnosing complex neuropathy syndromes is presented.
• An updated gene table for these conditions is provided.
• Understanding these genetic complexities is crucial for accurate diagnosis and management.