Objective: To describe a patient with the Dejerine-Sottas' syndrome due to a de novo Ser72Leu amino acid substitution in the PMP22 protein and summarize the phenotype associated with this frequent mutation.
Case report: The proband has a medical history of early onset, severe, and progressive demyelinating neuropathy, accompanied by mild ptosis and limitations of eye movements. Ulnar nerve motor conduction velocities were extremely reduced (2.6 and 2.2 m/s), and the sural nerve biopsy showed onion bulbs and thinly myelinated axons. Duplication of chromosome 17p11.2 was ruled out, and the Ser72Leu substitution was found upon sequencing the PMP22 gene.
Conclusion: The Ser72Leu substitution is being confirmed as the most frequent point mutation in the PMP22 gene. This 'hot spot' should be considered in the strategy of looking for point mutations in the hereditary demyelinating neuropathies.