Aims To describe two cases of Hereditary Neuropathy with Liability to Pressure Palsies (HNPP). To the best of our knowledge one of these is the first reported case of brachial plexus palsy in a neonate with HNPP.

Methods 2 Case reports.

Results The first case initially presented following Ventouse delivery at term with flexion deformities of both wrists felt to represent bilateral Klumpke's palsy. At day 6 the right side was normal but the left hand remained flexed with no active extension and the thumb was held in the palm. However, by 3 weeks she moved both hands freely.

At 12 years she re-presented with gradual onset left foot drop and sensory loss in L5/S1. This resolved over 2 months but then similar symptoms developed in the right foot. She also complained of intermittent pins and needles along the ulnar border of both hands.

Electrophysiology revealed a patchy demyelinating neuropathy with an emphasis on the points of usual compression. Genetic tests showed a 17p11.2 deletion and HNPP was diagnosed.

The second girl presented at 12 years with numbness along the ulnar distribution of the left hand followed by clawing. She has never had any other neuropathies although there was a paternal family history of nerve palsies.

As above, electrophysiology was typical of HNPP and there was a 17.p11.2 deletion. However, unusually for HNPP, the claw hand has persisted for 3 years although electrophysiology has returned to normal and therefore there is felt to be a functional element.

Conclusions HNPP is an autosomal dominant condition characterised by recurrent demyelinating mononeuropathies following minor trauma or compression. It typically presents with painless sensory and/or motor mononeuropathy during the 2nd to 3rd decade, most commonly affecting the peroneal or ulnar nerves. It causes reduced nerve conduction velocities and is associated with the peripheral myelin protein 22 gene. There is normally complete recovery.

This diagnosis should be considered in cases of repeated focal neuropathies and we suggest it should also be considered in neonates with unusual nerve palsies at birth.