Expanding the Clinical Spectrum of DRP2-Associated Charcot-Marie-Tooth Disease.

BACKGROUND AND OBJECTIVES: Germline truncating variants in the DRP2 gene (encoding dystrophin-related protein 2) cause the disruption of the periaxin-DRP2-dystroglycan complex and have been linked to Charcot-Marie-Tooth disease. However, the causality and the underlying phenotype of the genetic alterations are not clearly defined. METHODS: This cross-sectional retrospective observational study includes 9 patients with Charcot-Marie-Tooth disease (CMT) with DRP2 germline variants evaluated at 6 centers throughout Spain. RESULTS: We identified 7 Spanish families with 4 different DRP2 likely pathogenic germline variants. In agreement with an X-linked inheritance, men harboring hemizygous DRP2 variants presented with an intermediate form of CMT, whereas heterozygous women were asymptomatic. Symptom onset was variable (36.6 ± 16 years), with lower limb weakness and multimodal sensory loss producing a mild-to-moderate functional impairment. Nerve echography revealed an increase in the cross-sectional area of nerve roots and proximal nerves. Lower limb muscle magnetic resonance imaging confirmed the presence of a length-dependent fatty infiltration. Immunostaining in intradermal nerve fibers demonstrated the absence of DRP2 and electron microscopy revealed abnormal myelin thickness that was also detectable in the sural nerve sections. DISCUSSION: Our findings support the causality of DRP2 pathogenic germline variants in CMT and further define the phenotype as a late-onset sensory and motor length-dependent neuropathy, with intermediate velocities and thickening of proximal nerve segments.

IGF-1 in autosomal dominant cerebellar ataxia - open-label trial.

BACKGROUND: The objective of this clinical open-label trial was to test the safety, tolerability and efficacy of IGF-1 therapy for autosomal dominant cerebellar ataxia (ADCA) patients. RESULTS: A total of 19 molecularly confirmed patients with SCA3, 1 patient with SCA6 and 6 patients with SCA7 completed our study. They were 8 females and 18 males, 28 to 74 years of age (average ± SD: 49.3 ± 14.1). Patients were treated with IGF-1 therapy with a dosage of 50 µg/kg twice a day for 12 months. The efficacy of this therapy was assessed by change from baseline on the scale for the assessment and rating of ataxia (SARA). Ten patients, consecutively selected, continued their assigned dosages in a second year open-label extension trial. A statistically significant improvement in SARA scores was observed for patients with SCA3, patients with SCA7 and all patients grouped together after the first year of IGF-1 therapy, while a stabilization of the disease was confirmed during the second year (extension study). The single patient with SCA6 showed 3 improvement points in SARA score after 3 four-month periods of IGF-1 therapy when compared with baseline measurements. Our data indicate that IGF-1 is safe and well tolerated in general. CONCLUSIONS: Our data, in comparison with results from previous cohorts, indicate a trend for IGF-1 treatment to stabilize the disease progression for patients with SCA, indicating that IGF-1 therapy is able to decrease the progressivity of ADCA.

Triple therapy with darbepoetin alfa, idebenone, and riboflavin in Friedreich's ataxia: an open-label trial.

Minimal objective evidence exists regarding management of Friedreich's ataxia (FRDA). Antioxidant and recombinant human erythropoietin therapies have been considered potential treatments to slow progression of FRDA in a small number of studies. The primary objective of the current study was to test the efficacy, safety, and tolerability of triple therapy-darbepoetin alfa, idebenone, and riboflavin-in FRDA in a clinical pilot study. Patients included in this study were nine females, 16 to 45 years of age (average 28 ± 8), diagnosed with FRDA with confirmed GAA repeat expansion mutations in the FXN gene and a GAA repeat ≥400 on the shorter allele. Patients had a baseline score between 8 and 28.5 (average 20.7 ± 8.3) on the scale for the assessment and rating of ataxia and 94.3 ± 27.2 g/m(2) in left ventricular mass index (LVMI). Patients had been treated with triple therapy with 150 µg darbepoetin alfa every 2 or 3 weeks, 10-20 mg/kg/day idebenone, and 10-15 mg/kg/day riboflavin for 32 ± 19.4 months (range of 8-56 months). Triple therapy was tolerated. Although not statistically significant, improvement of ataxia was observed during the first six 4-month periods of the study. Furthermore, a small decrease in disease progression during the first 2 years of treatment was observed. Long-term statistically nonsignificant improvement of LVMI and stability of the echocardiographic parameters could be considered. Triple therapy may slow disease progression of FRDA.