Contribution of copy number variations in CMT1X: a retrospective study.

BACKGROUND AND PURPOSE: Charcot-Marie-Tooth disease type 1X (CMT1X) is an X-linked dominant hereditary motor-sensory peripheral neuropathy, which results from mutations in the Gap Junction B1 (GJB1) gene. In a few cases, gene deletions have been linked to the disease, but their relative contribution in the pathogenesis of CMT1X has not been assessed yet. Herein a retrospective study to establish the incidence of gene deletions is described. METHODS: Copy number variation analysis was performed by multiplex ligation-dependent probe amplification, whilst the breakpoints were defined by Sanger sequencing. RESULTS: A novel GJB1 deletion was identified in a family presenting with a classical CMT1X phenotype. The rearrangement includes the coding and the regulatory regions of GJB1. CONCLUSIONS: GJB1 deletions appear to be a rare but not insignificant cause of CMT1X and are associated with a typical disease phenotype. Accordingly, patients negative for point mutations whose pedigree and clinical records strongly suggest the possibility of CMT1X should be tested for GJB1 copy number variations.

Tinetti and Berg balance scales correlate with disability in hereditary peripheral neuropathies: a preliminary study.

BACKGROUND: The combination of distal muscle weakness, sensory defects and feet deformities leads to disequilibrium in patients affected by Charcot-Marie-Tooth (CMT) neuropathy. Studies relating the outcome of balance scales and clinical severity of CMT are lacking. AIM: To evaluate the accuracy of the Tinetti Balance scale (TBS) and Berg Balance scale (BBS) in identifying balance disorders and quantifying disease severity in CMT patients. DESIGN: Observational study. SETTING: University of Genoa-IRCCS AOU San Martino IST-Department of Neurology, Italy. POPULATION: Nineteen individuals with a diagnosis of CMT (12 females, 7 males, age 41.26±12.42). METHODS: All subjects underwent an evaluation with both TBS and BBS. Disability was quantified with CMT neuropathy score (CMTNS). Moreover, a complete neurophysiological study was performed. Distal lower limbs strength was evaluated with MRC scale. Pearson rank order correlation was used to determine the correlation between the scores on the two tests and to identify an eventual correlation between TBS or BBS and the CMTNS. RESULTS: Both scales showed a highly significant negative correlation with the CMTNS (r=-0.78, P<0.0005 and r=-0.77, P<0.001, respectively) and distal weakness on the anterior tibial muscles (AT) (TBS: AT left: r=0.65, P<0.005 and AT right: 0.59, P<0.01; BBS: AT left r=+0.71, P<0.001 and AT right r=+0.66, P<0.005). We found also a highly significant, positive correlation between the two different balance scales (r=+0.9, P<0.0001). CONCLUSION: TBS and BBS strongly correlate with disease disability and distal muscular weakness. CLINICAL REHABILITATION IMPACT: Both TBS and BBS may play a relevant role in the assessment of disability in patients affected by CMT. Further studies are needed to validate our results in a larger population.

Long-term oral contraceptive use does not affect trabecular bone density.

To determine whether long-term exposure to exogenous estrogen in oral contraceptives influences trabecular bone mass in premenopausal women, we studied 25 closely matched, healthy, premenopausal women, who were recruited from an active obstetrics and gynecology practice. Eleven women had never used oral contraceptives, and 14 women had used oral contraceptives for a minimum of 67 months. All oral contraceptive users had used preparations that provided a minimum of 50 micrograms mestranol per day. Trabecular bone density was determined by quantitative single-energy computerized tomography of the L1-3 lumbar vertebral bodies. Trabecular bone density was similar for both the control group and the oral contraceptive users, 160.6 +/- 6.9 versus 161.2 +/- 7.4 mg/ml, respectively. The power to detect a 15% difference in bone density between these two samples was 0.87. We concluded that long-term, premenopausal oral contraceptive use has no effect on vertebral bone density.

PIP: Although oral contraceptives (OCs) cause a depression of circulating estrogen to near postmenopausal levels, longterm OC use does not appear to lead to a reduction in trabecular bone density. In this study, trabecular bone density was determined by quantitative single-energy computerized tomography of the L1-3 lumbar vertebral bodies and compared in 14 longterm OC users (mean use of 120 months) and 11 never users. The controls and OC users were closely matched to eliminate as many potentially confounding variables as possible. Trabecular bone density was basically similar for both groups--160.6 + 6.9 for controls versus 161.2 + 7.4 mg/ml for cases. The power to detect a 15% difference in bone density between these 2 groups was 0.87. It is concluded that premenopausal OC use has neither a beneficial effect nor an appreciable negative effect on bone density after longterm use. If a threshold estrogen level is required for normal premenopausal bone remodeling, such a threshold is not reached by the depression of plasma estrogen levels during OC use. It should be noted that this study measured only the trabecular portion of vertebral bone, which is known to respond more rapidly than cortical bone to metabolic stimuli.