Autosomal dominant CMT-Type IB (Charcot-Marie-Tooth Neuropathy) as a differential diagnosis of clinically diagnosed autosomal recessive demyelinating CMT-Type 4E

Background information and Case report: CMT-Type 4E, or congenital hypomyelinating neuropathy (CHN) is an extremely rare disorder of myelin formation. Patients show early infantile hypotonia, distal muscle weakness, and areflexia. Complications are respiratory problems and swallowing difficulties. CHN is a genetically heterogenous disorder that results predominantly from autosomal recessive gene mutations.

The CMT-Type I shows a milder clinical course with a less severe progress in distal muscular weakness and atrophy. Autosomal dominant MPZ/PO-gene mutations are frequently found.

We report on two patients (mother and daughter) with clinical and histopathological picture of hypomyelinating CMT- Type 4E and autosomal dominant MPZ/PO-gene mutation in sense of a CMT-Type I.

Conclusion: Progress in molecular genetic diagnostics more frequently complicates the diagnosis of a certain kind of polyneuropathy. Often clinical presentation and genetic diagnosis do not match. Future molecular genetic research together with documentation of clinical and histopathological characteristics is required to further improve clinical and genetic classification of polyneuropathies.