P188. Gender-dependent differences in a cohort of Charcot-Marie-tooth (CMT) patients

Charcot-Marie-Tooth (CMT)-disease is the most common form of hereditary neuropathy and affects approximately 1 in 2500 people. It is inherited in an autosomal-dominant, -recessive or X-linked fashion (Gess et al., 2013). Mutations in >80 genes are known to cause CMT (CeGat). An effective treatment is not available yet. In this project, we aimed to test gender-dependent differences in CMT severity. Data from the German CMT patient registry (Friedrich-Baur-Institut) and our neuromuscular outpatient clinic were evaluated. 103 patients from Muenster (74.6%) with a genetically proven CMT were included. CMT1A built the largest sub-group with 67% (69 patients). The gender distribution was slightly unequal, with a surplus of women (41; 59.4%). The overall mean age was 47.4years (SD 13.3; men: 50.4/SD 15.5; women: 44.2/ SD 11.2). The examination consisted of patient history, muscle force testing (MRC grades divided into MRC⩾4 and ⩽3; foot dorsal extension dynamometry), nerve conduction studies (mNCV, CMAP, sNCV, SNAP) and CMT Neuropathy Scores (CMTNS and CMTNS-2). In a statistic analysis we assessed whether the CMTNS/CMTNS-2, muscle force, nerve conduction studies and foot operations differed in men and women and if they were dependent age. Men's mean CMTNS (18.2/SD 5.8) and CMTNS-2 (16.5/SD 5.6) were both higher than women's (16.4/SD 3.9 and 15.0/SD 4.1) within our patients. This difference was shown to be not significant ( p =0.249 and p =0.376). In a multivariate analysis with gender and age as covariates, gender showed to have no influence on both Neuropathy Scores ( p =0.527 for CMTNS, p =0.854 for CMTNS-2). However, age showed a highly significant influence on CMTNS and a trend on CMTNS-2 ( p =0.008 for n =59; p =0.085 for n =36). We could show that muscle force was not dependent of age or foot operations, but of gender. Regarding muscle force grades in the lower limb, statistically significant differences depending on gender could be found. The significance levels were p =0.029/0.006 (right/left) for dorsal extension and p =0.078/0.030 for plantar flexion of the foot. In the upper limbs, no difference with respect to gender could be detected. Within the small group of patients for whom we obtained these measurements ( n =27) no significant differences with respect to gender ( p =0.132 right, p =0.067 left) or age could be found. Examining the values for sensory/ motor nerve conduction velocities and nerve action potentials of the ulnar nerve on the non-dominant hand, we could not find any significant differences between men and women. SNAP showed a trend though ( p =0.087). Besides, we could show that age was negatively correlated to the values for CMAP ( p =0.003). Regarding foot operations, the relation of operated to non-operated patients was almost identical in both sexes. Taken together, this preliminary analysis of our ongoing study showed no significant difference in CMTNS scores, but significantly worse muscle force grades of the lower limbs in men compared to women, independent of age and foot surgery. Hence, there is the possibility that men with CMT1A lose their muscle strength (in the lower limbs) faster than women do.