The impact of interrupting enzyme replacement therapy in late-onset Pompe disease

Journal of Neurology - Late-onset Pompe disease (LOPD) is a rare autosomal recessive disorder caused by mutations in the GAA gene, leading to progressive weakness of locomotor and respiratory...     

Decreased water T2 in fatty infiltrated skeletal muscles of patients with neuromuscular diseases

Quantitative imaging techniques are emerging in the field of magnetic resonance imaging of neuromuscular diseases (NMD). T₂ of water (T_2w) is considered an important imaging marker to assess acute and chronic alterations of the muscle fibers, being generally interpreted as an indicator for “disease activity” in the muscle tissue. To validate the accuracy and robustness of quantitative imaging methods, ¹H magnetic resonance spectroscopy (MRS) can be used as a gold standard. The purpose of the present work was to investigate T_2w of remaining muscle tissue in regions of higher proton density fat fraction (PDFF) in 40 patients with defined NMD using multi‐TE single‐voxel ¹H MRS. Patients underwent MR measurements on a 3 T system to perform a multi‐TE single‐voxel stimulated echo acquisition method (STEAM) MRS (TE = 11/15/20/25(/35) ms) in regions of healthy, edematous and fatty thigh muscle tissue. Muscle regions for MRS were selected based on T₂‐weighted water and fat images of a two‐echo 2D Dixon TSE. MRS results were confined to regions with qualitatively defined remaining muscle tissue without edema and high fat content, based on visual grading of the imaging data. The results showed decreased T_2w values with increasing PDFF with R² = 0.45 (p < 10^?3) (linear fit) and with R² = 0.51 (exponential fit). The observed dependence of T_2w on PDFF should be considered when using T_2w as a marker in NMD imaging and when performing single‐voxel MRS for T_2w in regions enclosing edematous, nonedematous and fatty infiltrated muscle tissue.     

Side effects of anesthesia in DM2 as compared to DM1: a comparative retrospective study

Background and purpose: Myotonic dystrophy type 2 (DM2) is an adult‐onset progressive multisystem disease. There have been no reported risks for anesthesia in DM2. Methods: We assess the frequency, type, and severity of peri‐operative complications under general and local anesthesia in genetically proven DM2. A retrospective multicenter study was conducted. Results: Out of 320 DM2 patients, 134 participated by completing questionnaires (41, 88%), which were delivered by mail, and their clinical records were reviewed (class III evidence). A total of 121 patients had 340 operations in general anesthesia at an average age of 40.5 years (range 18–82); 132 (38.8%) general anesthesia were performed prior to DM2 onset, 187 (55.9%) after disease onset. A total of 212 (62.4%) of the interventions were performed without known DM2 diagnosis. In 120 (35.3%) interventions, DM2 was already diagnosed. The locations of surgery were lower abdomen (47%), peripheral extremities (46.8%), upper abdomen (3.8%), thorax (1.8%), and brain (0.6%). The overall frequency of severe complications was 0.6% (2 of 340). One incident was a post‐operative development of rhabdomyolysis, hyperthermia, muscle weakness and renal failure; the others, prolonged muscular weakness and renal failure. Minor complications related to a general anesthesia were reported by 27 participants (20.2%). In 116 patients (86.6%), 342 interventions were performed in regional anesthesia. Minor complications were reported by 20.2% participants such as nausea (6.7%), muscular weakness and pain (5.9%), prolonged anesthesia (5.2%), circulatory insufficiency (2.9%), and shortness of breath (2.9%). Conclusion: The overall lower risk seems to be predominantly related to the minor respiratory involvement in DM2, than in myotonic dystrophy type 1 (DM1).     

Coenzyme Q10 deficiency and isolated myopathy

Three unrelated, sporadic patients with muscle coenzyme Q10 (CoQ10) deficiency presented at 32, 29, and 6 years of age with proximal muscle weakness and elevated serum creatine kinase (CK) and lactate levels, but without myoglobinuria, ataxia, or seizures. Muscle biopsy showed lipid storage myopathy, combined deficiency of respiratory chain complexes I and III, and CoQ10 levels below 50% of normal. Oral high-dose CoQ10 supplementation improved muscle strength dramatically and normalized serum CK.     

Clinicopathological analysis of the homozygous p.W1327X AGL mutation in glycogen storage disease type 3

We report on clinicopathological and whole body MRI analyses of the index patient of a large nonconsanguineous German-Ukraine family with homozygous and heterozygous AGL gene mutations at position p.W1327X (c.3980G > A). There are only limited reports on this phenotype with a homozygous genotype. The index patient, a 49-year-old woman presented with hepatomegaly, cardiomyopathy and moderate progressive proximal limb myopathy. Skeletal muscle showed severe vacuolar myopathy with storage of PAS-positive non-membrane-limited glycogen. An increase in glycogen content and completely decrease of debranching enzyme activity was measured in erythrocytes. Mutational analysis of the AGL gene showed a homozygous p.W1327X mutation. In the family, two brothers had been affected by severe infantile onset hepatomegaly and died within their first years of life by fatal liver cirrhosis. Furthermore, another sister severely affected by hepatomegaly, cardiomyopathy and proximal skeletal myopathy died at age 33. Three younger heterozygous sisters and a brother noticed exercise-induced myalgia and weakness since their teens. In sum, a homozygous p.W1327X mutation leads to a severe generalized glycogenosis types 3a and 3b within the same family. Even heterozygous p.W1327X mutation carriers may present with mild non-progressive neuromuscular symptoms, such as exercise-induced myalgia and fatigue.     

Rippling muscle disease in childhood

Rippling muscle disease is a rare autosomal dominant disorder first described in 1975. Recently, it could be classified as a caveolinopathy; in European families, mutations in the caveolin-3 gene were revealed as causing this disease. Although clinical symptoms were almost all described in adulthood, we are now reporting clinical data of seven children with rippling muscle disease owing to mutations in the caveolin-3 gene. Initial symptoms were frequent falls, inability to walk on heels, tiptoe walking with pain and a warm-up phenomenon, calf hypertrophy, and an elevated serum creatine kinase level. Percussion-/pressure-induced rapid contractions, painful muscle mounding, and rippling could be observed even in early childhood. The diagnosis can be confirmed by molecular genetic analysis. Muscle biopsy must be considered in patients without muscle weakness or mechanical hyperirritability to differentiate between rippling muscle disease and limb-girdle muscular dystrophy 1C.     

Sudden cardiac death in myotonic dystrophy type 2

Medical records and follow-up data were reviewed in 297 genetically proven myotonic dystrophy type 2 (DM2) patients. Patients were selected by the criteria of cardiac sudden death before age 45. Sudden death occurred in four patients, three of whom were cardiological asymptomatic, and one with a history of heart failure. Cardiac histopathology showed dilated cardiomyopathy in all, and conduction system fibrosis in two patients. Pathogenetic CCUG ribonuclear inclusions were demonstrable in cardiomyocytes.