Mutational analysis of Greek patients with suspected hereditary neuropathy with liability to pressure palsies (HNPP): a 15‐year experience. Issue 2 (June 2015)

• Record Type: Journal Article
• Authors: Karadima, Georgia; Koutsis, Georgios; Raftopoulou, Maria; Karletidi, Karolina‐Maria; Zambelis, Thomas; Karandreas, Nikolaos; Panas, Marios
• Is Part Of: Journal of the peripheral nervous system. Volume 20:Issue 2(2015)
• Page Start: 79
• Page End: 85
• Publication Date: 2015-06
• Subjects: Nervous system -- Periodicals; Nerves, Peripheral -- Diseases -- Periodicals; Peripheral Nervous System Diseases -- Periodicals; Peripheral Nervous System -- Periodicals; 612.81
• DOI: 10.1111/jns.12125
• Languages: English
• ISSNs: 1085-9489

Abstract

<abstract abstract-type="main" id="jns12125-abs-0001"> <title>Abstract</title> <p id="jns12125-para-0001">There has been limited information from population studies regarding the overall frequency of the common 1.5‐Mb 17p11.2 deletion and even scarcer data regarding the overall frequency of <italic>PMP22</italic> micromutations in patients with a clinical suspicion of hereditary neuropathy with liability to pressure palsies (HNPP). We have analysed 100 consecutive Greek patients referred for HNPP genetic testing over a 15‐year period to our Neurogenetics Unit in Athens, a reference centre for all regions of Greece. All patients were screened for the 1.5‐Mb deletion and a selected subgroup of deletion‐negative patients for <italic>PMP22</italic> micromutations. Mutation‐positive and mutation‐negative patients were compared for various clinical parameters. In total, 54 mutation‐positive patients were identified. In index cases, the deletion frequency was 47.8%, and the <italic>PMP22</italic> micromutation frequency was 2.2%. Within mutation‐positive patients, the common deletion represented 95.7% and <italic>PMP22</italic> micromutations 4.3% of cases. Two previously reported <italic>PMP22</italic> micromutations (c.364_365delCC and c.79‐2A>G) were detected. HNPP index cases had a 2.8–1 male‐to‐female ratio, similar to mutation‐negative patients. A typical phenotype (recurrent or isolated palsies) was present in 82.4% of symptomatic HNPP cases, significantly higher than mutation‐negative patients. Sensitivity of proposed electrophysiological diagnostic criteria for HNPP was calculated at 95.7% and specificity at 80.5%. In conclusion, the common HNPP deletion accounts for ∼50% and <italic>PMP22</italic> micromutations for ∼2% of cases in a large consecutive cohort of patients with suspected HNPP. The mutational and phenotypic spectrum of HNPP is similar in the Greek population compared with other populations. Proposed electrophysiological diagnostic criteria perform satisfactorily in everyday clinical practice.</p> </abstract>