Clinical, histological and genetic characterization of reducing body myopathy caused by mutations in FHL1.

We recently identified the X-chromosomal four and a half LIM domain gene FHL1 as the causative gene for reducing body myopathy, a disorder characterized by progressive weakness and intracytoplasmic aggregates in muscle that exert reducing activity on menadione nitro-blue-tetrazolium (NBT). The mutations detected in FHL1 affected highly conserved zinc coordinating residues within the second LIM domain and lead to the formation of aggregates when transfected into cells. Our aim was to define the clinical and morphological phenotype of this myopathy and to assess the mutational spectrum of FHL1 mutations in reducing body myopathy in a larger cohort of patients. Patients were ascertained via the detection of reducing bodies in muscle biopsy sections stained with menadione-NBT followed by clinical, histological, ultrastructural and molecular genetic analysis. A total of 11 patients from nine families were included in this study, including seven sporadic patients with early childhood onset disease and four familial cases with later onset. Weakness in all patients was progressive, sometimes rapidly so. Respiratory failure was common and scoliosis and spinal rigidity were significant in some of the patients. Analysis of muscle biopsies confirmed the presence of aggregates of FHL1 positive material in all biopsies. In two patients in whom sequential biopsies were available the aggregate load in muscle sections appeared to increase over time. Ultrastructural analysis revealed that cytoplasmic bodies were regularly seen in conjunction with the reducing bodies. The mutations detected were exclusive to the second LIM domain of FHL1 and were found in both sporadic as well as familial cases of reducing body myopathy. Six of the nine mutations affected the crucial zinc coordinating residue histidine 123. All mutations in this residue were de novo and were associated with a severe clinical course, in particular in one male patient (H123Q). Mutations in the zinc coordinating residue cysteine 153 were associated with a milder phenotype and were seen in the familial cases in which the boys were still more severely affected compared to their mothers. We expect the mild end of the spectrum to significantly expand in the future. On the severe end of the spectrum we define reducing body myopathy as a progressive disease with early, but not necessarily congenital onset, distinguishing this condition from the classic essentially non-progressive congenital myopathies.

Three complementary definitions of polypharmacy: methods, application and comparison of findings in a large prescription database.

PURPOSE: To develop and compare three operational definitions of polypharmacy using a large prescription database. METHODS: We defined Cumulative polypharmacy as all prescriptions filled during a 178 day window--which captured 95% of eventual refills as calculated from Kaplan-Meier and cumulative incidence curves. Continuous polypharmacy was all prescriptions filled in two such windows 6 months apart. Simultaneous polypharmacy was the number of prescriptions active on a particular day, as determined by fill dates and amount of medication given. We applied these definitions to the outpatient prescription files of New England veterans and compared the resulting estimates of polypharmacy using descriptive statistics. RESULTS: 118,013 patients received at least one prescription between January 1998 and July 1999. Cumulative polypharmacy averaged 3.54 (SD = 4.95) medications and continuous polypharmacy averaged 1.96 (SD = 3.23). Examination of simultaneous polypharmacy over 40 2-week intervals revealed an average of 2.63 (CI 2.61-2.65), a minimum of 1.09 (CI 1.08-1.10) and maximum of 4.94 (CI 4.92-4.96). One arbitrarily selected observation point had an average of 3.87 (SD = 3.17). CONCLUSIONS: Our definitions of cumulative and continuous polypharmacy serve to set upper and lower bounds for the estimate of polypharmacy. Our method for simultaneous polypharmacy gives numbers that diverge in some respects, but it is better at showing transient changes in medications. The methods are complementary and allow exploration of various aspects of medication use, such as cumulative medication exposure over time, the influence of chronic medical problems, and the causes of rapid changes in medications.