Ataluren delays loss of ambulation and respiratory decline in nonsense mutation Duchenne muscular dystrophy patients

Aim: We investigated the effect of ataluren plus standard of care (SoC) on age at loss of ambulation (LoA) and respiratory decline in patients with nonsense mutation Duchenne muscular dystrophy (nmDMD) versus patients with DMD on SoC alone. / Patients & methods: Study 019 was a long-term Phase III study of ataluren safety in nmDMD patients with a history of ataluren exposure. Propensity score matching identified Study 019 and CINRG DNHS patients similar in disease progression predictors. / Results & conclusion: Ataluren plus SoC was associated with a 2.2-year delay in age at LoA (p = 0.0006), and a 3.0-year delay in decline of predicted forced vital capacity to <60% in nonambulatory patients (p = 0.0004), versus SoC. Ataluren plus SoC delays disease progression and benefits ambulatory and nonambulatory patients with nmDMD. / ClinicalTrials.gov: NCT01557400

G.P.147 - Outcome measures for Duchenne muscular dystrophy from ambulant to non-ambulant: implications for clinical trials

Novel emerging therapies for Duchenne muscular dystrophy (DMD), such as antisense oligomer (AO) mediated exon skipping, have generated the need of understanding the natural history study of the targeted genotype subgroups. Most natural history studies are focused on ambulant subjects; therefore very little data exists on non-ambulant DMD. Specifically targeting skippable deletions, we aim to assess the natural history of DMD through a composite assessment tool capable of capturing disease progression beyond loss of ambulation

Meta-analyses of ataluren randomized controlled trials in nonsense mutation Duchenne muscular dystrophy.

Aim: Assess the totality of efficacy evidence for ataluren in patients with nonsense mutation Duchenne muscular dystrophy (nmDMD). Materials & methods: Data from the two completed randomized controlled trials (ClinicalTrials.gov: NCT00592553; NCT01826487) of ataluren in nmDMD were combined to examine the intent-to-treat (ITT) populations and two patient subgroups (baseline 6-min walk distance [6MWD] \u3e= 300-\u3c400 or \u3c400 m). Meta-analyses examined 6MWD change from baseline to week 48.Results:Statistically significant differences in 6MWD change with ataluren versus placebo were observed across all three meta-analyses. Least-squares mean difference (95% CI): ITT (n = 342), +17.2 (0.2-34.1) m, p = 0.0473; \u3e= 300-\u3c400 m (n = 143), +43.9 (18.2-69.6) m, p = 0.0008; \u3c400 m (n = 216), +27.7 (6.4-49.0) m, p = 0.0109. Conclusion: These meta-analyses support previous evidence for ataluren in slowing disease progression versus placebo in patients with nmDMD over 48 weeks. Treatment benefit was most evident in patients with a baseline 6MWD \u3e= 300-\u3c400 m (the ambulatory transition phase), thereby informing future trial design

Walker-Warburg syndrome

Walker-Warburg Syndrome (WWS) is a rare form of autosomal recessive congenital muscular dystrophy associated with brain and eye abnormalities. WWS has a worldwide distribution. The overall incidence is unknown but a survey in North-eastern Italy has reported an incidence rate of 1.2 per 100,000 live births. It is the most severe form of congenital muscular dystrophy with most children dying before the age of three years. WWS presents at birth with generalized hypotonia, muscle weakness, developmental delay with mental retardation and occasional seizures. It is associated with type II cobblestone lissencephaly, hydrocephalus, cerebellar malformations, eye abnormalities and congenital muscular dystrophy characterized by hypoglycosylation of α-dystroglycan. Several genes have been implicated in the etiology of WWS, and others are as yet unknown. Several mutations were found in the Protein O-Mannosyltransferase 1 and 2 (POMT1 and POMT2) genes, and one mutation was found in each of the fukutin and fukutin-related protein (FKRP) genes. Laboratory investigations usually show elevated creatine kinase, myopathic/dystrophic muscle pathology and altered α-dystroglycan. Antenatal diagnosis is possible in families with known mutations. Prenatal ultrasound may be helpful for diagnosis in families where the molecular defect is unknown. No specific treatment is available. Management is only supportive and preventive

Assignment of a Form of Congenital Muscular Dystrophy with Secondary Merosin Deficiency to Chromosome 1Q42

We have previously reported an autosomal recessive form of congenital muscular dystrophy, characterized by proximal girdle weakness, generalized muscle hypertrophy, rigidity of the spine, and contractures of the tendo Achilles, in a consanguineous family from the United Arab Emirates. Early respiratory failure resulting from severe diaphragmatic involvement was present. Intellect and the results of brain imaging were normal. Serum creatine kinase levels were grossly elevated, and muscle-biopsy samples showed dystrophic changes. The expression of the laminin-alpha 2 chain of merosin was reduced on several fibers, but linkage analysis excluded the LAMA2 locus on chromosome 6q22-23. Here, we report the results of genomewide linkage analysis of this family, by use of homozygosity mapping. In all four affected children, an identical homozygous region was identified on chromosome 1q42, spanning 6-15 cM between flanking markers D1S2860 and D1S2800. We have identified a second German family with two affected children having similar clinical and histopathological features; they are consistent with linkage to the same locus. The cumulative LOD score was 3.57 (theta = .00) at marker D1S213. This represents a novel locus for congenital muscular dystrophy. We suggest calling this disorder "CMD1B.'' The expression of three functional candidate genes in the CMD1B critical region was investigated, and no detectable changes in their level of expression were observed. The secondary reduction in laminin-alpha 2 chain in these families suggests that the primary genetic defect resides in a gene coding for a protein involved in basal lamina assembly

Spectrum Of Brain Changes In Patients With Congenital Muscular Dystrophy And Fkrp Gene Mutations

Objectives: To report the spectrum of brain magnetic resonance imaging findings in 13 patients with congenital muscular dystrophy and FKRP gene mutations and to explore possible geno type-phenotype correlations. Design: We retrospectively reviewed brain magnetic resonance imaging in patients with congenital muscular dystrophy and FKRP gene mutations. Patients: Thirteen patients with congenital muscular dystrophy and mutations in the FKRP gene. Results: Five of the 13 patients had the typical phenotype originally described for congenital muscular dystrophy (MDC1C) with normal intelligence and normal brain magnetic resonance imaging while 3 other patients had isolated cerebellar cysts and mental retardation without any other sign of posterior fossa of supratentorial abnormalities. In the remaining 5 patients cerebellar cysts were associated with structural brain changes involving the posterior fossa and the cortex, ranging from focal unilateral periventricular nodular heterotopia to marked cerebellar dysplasia and pontine hypoplasia. In 2 of these 5 patients the severity and distribution of changes resembled muscle-eye-brain disease in 1 patient who had mild Walker-Warburg syndrome. The distribution of FKRP gene mutations identified in this group of patients did not reveal any obvious association with the severity of central nervous system involvement. Conclusions: The severity of central nervous system involvement observed in our patients in contrast broadly reflected the severity of the disruption of alpha-dystroglycan glycosylation. In particular, dystroglycan expression was almost absent in the patients with muscle-eye-brain diseaselike phenotype and less severely reduced in the patients with congenital muscular dystrophy (MDC1C) with or without cerebellar cysts. This study further highlights the central role that dystroglycan has in neuronal migration.WoSScopu