Proptosis in a family with the p16 Leuc-to-Prol mutation in the PMP22 gene (CMT 1E)

Charcot-Marie-Tooth disease (CMT) is the most common neuromuscular disorder.The autosomal dominant and demyelinating type (CMT1) associated with duplication of the PMP22 gene (CMT1A) is the most prevalent subtype around the world, including Brazil 1 , and is typically associated with mild or moderate neuropathy.Point mutations in the same gene (CMT1E) are extremely rare 2 and typically result in severe demyelinating neuropathies, including Dejerine-Sottas syndrome and congenital hypomyelinating neuropathy 3 .Interestingly, CMT1 patients harboring the same mutation may develop different manifestations, even in identical twins.Herein, we present Brazilian siblings harboring a previously described point mutation in the PMP22 gene that manifested as an unexpected clinical phenotype.