The Clinical,Electrophysiological And Genetic Analysis On Three Pedigrees Of Hereditary Neuropathy With Liability To Pressure Palsies

Objective:In this study,we retrospectively reviewed the clinical and electrophysiological characteristics of hereditary neuropathy with liability to pressure palsies(HNPP),investigated the value of multiplex ligation-dependent probe amplification(MLPA)technique in the genetic diagnosis in HNPP patients,and further studied thier gene mutation to promote the understanding and diagnosis of the disease among clinicians.Materials and Method:Ten cases from three pedigree who were diagnosed in the Department of Neurology,first Hospital of Jilin University during the period from2013 to 2016 were examined in detail and were carried out electrophysiological examination.The gene mutation of human peripheral myelin protein 22(PMP22)gene was detected by MLPA technique.Result:1.Clinical characteristics:In this study,all ten HNPP patients had positive family history,and the average age of onset of our patients was in their second decade.The main clinical presentations that most of the patients with HNPP from our cohort suffered from were limb numbness and weakness triggered by slight stretch or compression to nerve at common sites of entrapment.Nine of the ten patients fully recovered,and only one case presented with atrophy of the muscle.2.Electrophysiological examination characteristics:Four of ten patients with HNPP from three pedigrees underwent electrophysiological examination.No matter whether they had clinical symptoms or not,the electrophysiological examination showed that sensory and motor nerve conduction velocities were often decreased and distal motor latencies was prolonged.3.Gene testing result:Gene testing exhibited a 1.5-megabase deletion on chromosome17p11.2 bearing the peripheral myelin protein 22(PMP22)gene in all 6patients(including 3 proband).Conclusions:(1)The clinical symptoms of the patients in our group were numbness and muscle weakness in the easily affected nerves,but the symptoms were mild.And the positive fanmily history is consistent with autosomal dominant inheritance.(2)The characteristic electrophysiologic manifestation of HNPP is of great significance for clinical diagnosis.(3)Gene detection finally testified that all the patients of our group were caused by a 1.5-megabase deletion on chromosome 17p11.2 with PMP22 gene,which is also the main type of gene mutation of HNPP patients in china.(4)MLPA technique plays an important role in the diagnosis of HNPP.