Objective:

To highlight an unusual case of a patient with an entire sequence deletion of PMP22 who presents with a phenotype of a length-dependent, sensorimotor peripheral neuropathy and clubfoot.

Background:

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disorder caused by a deletion involving the PMP22 gene, or less frequently a PMP22 sequence variant. It is phenotypically characterized by episodic mononeuropathies with painless attacks of numbness, weakness, and atrophy preceded by minor compression of a nerve. Full recovery from the acute mononeuropathies is typically seen. Duplications of the PMP22 gene lead to Charcot-Marie-Tooth disease type 1A (CMT1A). This is clinically characterized by distal symmetric muscle weakness and atrophy (there can be a “stork appearance” to the legs due to atrophy), foot deformity (most commonly pez cavus), and sensory loss.

Design/Methods:

NA

Results:

The patient is a 50-year-old male who presented due to PMP22 deletion (entire sequence). He primarily described foot problems. He was diagnosed with clubfoot in infancy, and subsequently underwent over 13 foot and ankle surgeries. He denied episodes with lasting discrete areas of numbness or weakness. The patient’s daughter, who also has the same sequence deletion, is followed for recurrent ulnar neuropathy at the elbow. Exam revealed symmetric, severe atrophy of the lower legs and feet, with mild proximal weakness in the legs, unclear distal strength on limited assessment due to ankle surgeries/fusions, intact arm strength, length dependent sensory loss of large and small fiber function, absent left ankle jerk but otherwise intact reflexes, and sway on romberg.

Conclusions:

This case expands the genotype-phenotype correlation of PMP22 deletions where a patient with an entire sequence PMP22 deletion presented more like CMT1A rather than HNPP.