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Regular health checkups for mothers of patients with Duchenne muscular dystrophy have been performed at National Hospital Organization Tokushima Hospital since 1994. Among 43 mothers participated in this study, 28 dystrophinopathy carriers were identified. Skeletal and cardiac muscle functions of these subjects were examined. High serum creatine kinase was found in 23 subjects (82.1%). Obvious muscle weakness was present in 5 (17.8%) and had progressed from 1994 to 2015. Cardiomyopathy was observed in 15 subjects (60.0%), including dilated cardiomyopathy-like damage that was more common in the left ventricular (LV) posterior wall. Late gadolinium enhancement on cardiac MRI was found in 5 of 6 subjects, suggesting fibrotic cardiac muscle. In speckle tracking echocardiography performed seven years later, global longitudinal strain was decreased in these subjects, indicating LV myocardial contractile abnormality. These results suggest that female dystrophinopathy carriers should receive regular checkups for detection and treatment of cardiomyopathy, even if they have no cardiac symptoms.

A new homozygous alpha-sarcoglycan (adhalin) gene mutation was found in a Japanese patient with severe childhood autosomal recessive muscular dystrophy (SCARMD). Muscle biopsy specimens from the patient showed marked reduction but not complete deficiency of alpha-sarcoglycan. The sequence of part of exon 3 of the alpha-sarcoglycan gene exhibited a cytosine to thymidine substitution at nucleotide position 220. Since the same mutation was not found in 100 normal control samples, this new alpha-sarcoglycan gene mutation is not a polymorphism but is presumed to be responsible for the marked reduction of alpha-sarcoglycan in skeletal muscle. Most patients with homozygous alpha-sarcoglycan gene mutation were reported to show complete alpha-sarcoglycan deficiency. Present case showed the homozygous missense mutation of alpha-sarcoglycan and associated with incomplete alpha-sarcoglycan deficiency and severe clinical phenotype.

Two siblings who exhibited hereditary parkinsonism with pyramidal signs and cerebellar ataxia are reported. Anticholinergics had a dramatic beneficial effect in both cases, but levodopa did not. This responsiveness, which is similar to that reported in patients with Joseph's disease, suggests dysfunction of an “indirect pathway” involving the globus pallidus and the subthalamic nucleus, in addition to that of the nigrostriatal system. We propose a new hereditary variant of early onset Parkinson's disease, distinct from the levodopa sensitive forms of juvenile Parkinson's disease.

To estimate the oxidative damage to skeletal muscle DNA in mitochondrial encephalomyopathies, we studied the amount of 8-hydroxy-deoxyguanosine (8-OH-dG) and the localization of superoxide dismutase (SOD) in the skeletal muscles of patients with progressive external ophthalmoplegia (PEO) or Kearns-Sayre syndrome (KSS). The molar ratio of 8-OH-dG/deoxyguanosine in skeletal muscle from PEO or KSS patients was significantly higher than the control value. The ratio from patients with polymyositis or Duchenne's muscular dystrophy was not significantly elevated. Immunohistochemical staining for both Mn-SOD and Cu,Zn-SOD showed pronounced staining in the subsarcolemmal and intermyofibrillar regions of cytochrome-oxidase-negative ragged red fibers of KSS or PEO muscles. Our findings suggest that overproduction of 8-OH-dG and mitochondrial dysfunction with gene deletions are associated with each other in muscle cells of patients with PEO or KSS, and that free radicals may play an important role in the pathophysiology of mitochondrial encephalomyopathies.