OBJECTIVE: To redefine phenotypical characteristics for both chloride (ClCh) and sodium channelopathies (NaCh) in non-dystrophic myotonic syndromes (NDM). METHODS: In a cross-sectional, nationwide study, standardised interviews and clinical bedside tests were performed in 62 genetically confirmed NDM patients, 32 ClCh and 30 NaCh. RESULTS: Standardised interviews revealed that ClCh reported a higher frequency of muscle weakness (75 vs 36.7%; p<0.01), the warm-up phenomenon (100 vs 46.7%; p<0.001), and difficulties in standing up quickly (90.6 vs 50.0%; p<0.001), running (90.6% vs 66.7; p<0.05) and climbing stairs (90.6 vs 63.3%; p = 0.01). Patients with NaCh reported an earlier onset (4.4 vs 9.6 years; p<0.001), and higher frequencies of paradoxical (50.0 vs 0%; p<0.001) and painful myotonia (56.7 vs 28.1%; p<0.05). Standardised clinical bedside tests showed a higher incidence and longer relaxation times of myotonia in the leg muscles for ClCh (100 vs 60%; mean duration of chair tests 12.5 vs 6.3 s; p<0.001), and in eyelid muscles for NaCh (96.7 vs 46.9%; mean relaxation time of 19.2 vs 4.3 s; p<0.001). Transient paresis was only observed in ClCh (62.5%) and paradoxical myotonia only in NaCh (30.0%). Multivariate logistic regression analyses allowed clinical guidelines to be proposed for genetic testing. CONCLUSION: This study redefined the phenotypical characteristics of NDM in both ClCh and NaCh. The clinical guidelines proposed may help clinicians working in outpatient clinics to perform a focused genetic analysis of either CLCN1 or SCN4A.
OBJECTIVE: To redefine phenotypical characteristics for both chloride (ClCh) and sodium channelopathies (NaCh) in non-dystrophic myotonic syndromes (NDM). METHODS: In a cross-sectional, nationwide study, standardised interviews and clinical bedside tests were performed in 62 genetically confirmed NDM patients, 32 ClCh and 30 NaCh. RESULTS: Standardised interviews revealed that ClCh reported a higher frequency of muscle weakness (75 vs 36.7%; p<0.01), the warm-up phenomenon (100 vs 46.7%; p<0.001), and difficulties in standing up quickly (90.6 vs 50.0%; p<0.001), running (90.6% vs 66.7; p<0.05) and climbing stairs (90.6 vs 63.3%; p = 0.01). Patients with NaCh reported an earlier onset (4.4 vs 9.6 years; p<0.001), and higher frequencies of paradoxical (50.0 vs 0%; p<0.001) and painful myotonia (56.7 vs 28.1%; p<0.05). Standardised clinical bedside tests showed a higher incidence and longer relaxation times of myotonia in the leg muscles for ClCh (100 vs 60%; mean duration of chair tests 12.5 vs 6.3 s; p<0.001), and in eyelid muscles for NaCh (96.7 vs 46.9%; mean relaxation time of 19.2 vs 4.3 s; p<0.001). Transient paresis was only observed in ClCh (62.5%) and paradoxical myotonia only in NaCh (30.0%). Multivariate logistic regression analyses allowed clinical guidelines to be proposed for genetic testing. CONCLUSION: This study redefined the phenotypical characteristics of NDM in both ClCh and NaCh. The clinical guidelines proposed may help clinicians working in outpatient clinics to perform a focused genetic analysis of either CLCN1 or SCN4A.
Authors: Bas C Stunnenberg; Joost Raaphorst; Hans M Groenewoud; Jeffrey M Statland; Robert C Griggs; Willem Woertman; Dick F Stegeman; Janneke Timmermans; Jaya Trivedi; Emma Matthews; Christiaan G J Saris; Bas J Schouwenberg; Gea Drost; Baziel G M van Engelen; Gert Jan van der Wilt Journal: JAMA Date: 2018-12-11 Impact factor: 56.272
Authors: Bas C Stunnenberg; Samantha LoRusso; W David Arnold; Richard J Barohn; Stephen C Cannon; Bertrand Fontaine; Robert C Griggs; Michael G Hanna; Emma Matthews; Giovanni Meola; Valeria A Sansone; Jaya R Trivedi; Baziel G M van Engelen; Savine Vicart; Jeffrey M Statland Journal: Muscle Nerve Date: 2020-05-27 Impact factor: 3.217
Authors: Emma Matthews; James A L Miller; Malcolm R MacLeod; James Ironside; Gareth Ambler; Robin Labrum; Richa Sud; Janice L Holton; Michael G Hanna Journal: Muscle Nerve Date: 2011-06-22 Impact factor: 3.217
Authors: Jeffrey M Statland; Brian N Bundy; Yunxia Wang; Jaya R Trivedi; Dipa Raja Rayan; Laura Herbelin; Merideth Donlan; Rhonda McLin; Katy J Eichinger; Karen Findlater; Liz Dewar; Shree Pandya; William B Martens; Shannon L Venance; Emma Matthews; Anthony A Amato; Michael G Hanna; Robert C Griggs; Richard J Barohn Journal: Muscle Nerve Date: 2012-10 Impact factor: 3.217