Emanuele Rastelli

Recurrent hyperCKemia with normal muscle biopsy in a pediatric patient with neuromyelitis optica

Neuromyelitis optica (NMO) is a demyelinating disease of the CNS that preferentially affects the optic nerve and spinal cord.1 The presence of circulating autoantibodies (NMO–immunoglobulin G [IgG]) having the water channel aquaporin-4 (AQP-4) as their target antigen is associated with NMO.1 Outside the CNS AQP-4 is present in the distal collecting tubes of the kidney, in parietal cells of the stomach,2 and in fast-twitch fibers of skeletal muscle.3 Several findings support the idea that AQP-4 water channels may be associated to the dystrophin-glycoprotein complex (DGC) in skeletal muscle fibers and AQP-4 expression has been found altered in muscle diseases.4

An Age-Standardized Prevalence Estimate and a Sex and Age Distribution of Myotonic Dystrophy Types 1 and 2 in the Rome Province, Italy

Background: Prevalence estimates for the 2 forms of myotonic dystrophy types 1 and 2 (DM1 and DM2) are not exhaustive or non-available. Our aim was to estimate the minimum prevalence of DM1 and DM2 in Italy in the Rome province, applying standards of descriptive epidemiology. Methods: All patients with a molecular diagnosis of DM1/DM2 and residents in the Rome province in 2013 have been enrolled, and the age-standardized prevalence has been calculated, assuming a Poisson distribution and adjusting for age. Results: We identified 395 DM1 patients: the age-standardized prevalence for total, females and males was 9.65, 8.35 and 11.07/100,000, respectively. The mean age of subjects differed considerably according to CTG repeat length (p = 0.001). Forty DM2 patients were identified. The age-standardized prevalence for total, females and males was 0.99, 1.07 and 0.90/100,000, respectively. The mean age was 57.05. Conclusions: We estimated for the first time the age-standardized prevalence and the sex and age distribution of DM1 and DM2 in a general population. A higher prevalence of males in DM1 and females in DM2 and a higher mean age of DM2 patients (+8 years) were ascertained. Prevalence of DM2 was 10% that of DM1. These prevalence values are probably lower than mutational rates due to the incomplete penetrance of DM1 mutations and to the clinical elusiveness of DM2. Our findings will be useful in designing cohort studies and for developing a disease registry.

Neutral lipid storage disease with myopathy and extended phenotype with novel PNPLA2 mutation

Neutral lipid‐storage disease with myopathy is caused by mutations in PNPLA2, which produce skeletal and cardiac myopathy. We report a man with multiorgan neutral lipid storage and unusual multisystem clinical involvement, including cognitive impairment.

Cutaneous features of myotonic dystrophy types 1 and 2: implication of premature aging and vitamin d homeostasis

Skin changes have been described in myotonic dystrophy type 1 (DM1). However, whether and in which way skin is a target of specific disease alterations in DM1 and DM2 has not been yet clarified. This study aims to explore cutaneous features of DM1 and DM2 patients. Skin examination was performed in 60 DM1, 15 DM2, and 103 control, unselected patients by means of dermoscopy. It revealed quantitative and qualitative abnormalities of nevi and typical signs of premature aging in both DM1 and DM2 patients, with a significantly higher frequency of dysplastic nevi, alopecia, xerosis and seborrheic dermatitis. Twenty-eight nevi were excised in DM patients and none showed histological features of melanoma, although 12 of them were diagnosed as dysplastic and the remaining 16 presented histological irregularity in melanin distribution. In DM1 patients, the number of nevi correlated with CTG expansion size, whereas the presence of dysplastic nevi and xerosis inversely correlated with vitamin D levels. DM1 and DM2 patients display a high frequency of skin abnormalities, the most common of which correlate with genotype severity and serum vitamin D levels. Skin examination is highly informative in these patients and reveals features suggestive of premature aging and impaired vitamin D homeostasis.

Erratum to: Increased risk of tumor in DM1 is not related to exposure to common lifestyle risk factors.

Recent studies documented an increased risk of neoplasm in patients with myotonic dystrophies (DM). Yet, none of these studies evaluated the contribution of common cancer risk factors in such observation. In this study, we included a cohort of patients (n = 255) with an established molecular diagnosis of DM type 1 (DM1), and who receives their treatment in one of the four centers with recognized expertise in neuromuscular disorders in Rome. We estimated the prevalence of benign and malignant tumors, and assessed if lifestyle factors and/or specific disease features would be associated to their occurrence. Overall, 59 benign tumors in 54 patients and 19 malignant tumors in 17 patients were diagnosed. The most common malignant neoplasms were cancers of the skin (31.6 %), thyroid (21.0 %), ovary (10.5 %), and breast (10.5 %). Uterine fibroid was the most common benign tumor (37.6 %) in women, while pilomatricoma was the most common in men (28.6 %). Age at enrollment (OR = 1.02, 95 % CI 1.00–1.05), and female gender (OR = 5.71, 95 % CI 2.90–11.22) were associated with tumor development in DM1 patients, while thyroid disorders was associated with malignant tumors only in women (OR = 5.12, 95 % CI 1.35–19.37). There was no association between tumor development and evaluated lifestyle factors. In conclusion, the lack of association between common cancer risk factors and tumor development in DM1 support a pathogenic link between tumors and DM1 itself, emphasizing the need for a systematic surveillance. Our observation of an association between thyroid diseases in women and cancer development needs confirmation.

Neurofibromatous neuropathy: An ultrastructural study

ABSTRACT Plexiform neurofibroma is pathognomonic of neurofibromatosis 1 (NF1). An NF1-associated peripheral neuropathy has been described in a small minority of NF1 patients but its histopathological features are poorly characterized. We report the case of a 46-year-old woman presenting with bilateral supraclavicular painful masses without other stigmata of NF1. MRI showed bilateral plexiform lesions extending from cervical roots to the elbows. Nerve conduction studies documented a sensory motor polyneuropathy. Morphometric analysis of sural nerve biopsy showed a preferential loss of large-caliber myelinated fibers with a g ratio of 0.515, and the presence of regeneration clusters. By electron microscopy, marked and diffuse endoneurial fibrosis with an altered relationship between Schwann cells (SC) and collagen fibrils was observed. Moreover both myelinating and non-myelinating SC were characterized by the presence of various cell degradation products. These changes suggest that, in neurofibromatous neuropathy, a widespread axonal atrophy and degeneration take place independently on the presence of tumoral infiltration, possibly due to an impairment in SC-axon cross talk. In this case, the coexistence of plexiform neurofibromas with a peripheral neuropathy strongly suggests a diagnosis of NF1 even without fulfillment of clinical criteria. We propose that in the presence of plexiform neurofibromas, electrophysiological studies should be performed also in asymptomatic patients, in order to detect the existence of a subclinical neuropathy.

Validation of the Nine Hole Peg Test as a measure of dexterity in myotonic dystrophy type 1

We aimed to validate the Nine Hole Peg Test as a measure of dexterity in myotonic dystrophy type 1 (DM1). Fifty patients with adult-onset, genetically confirmed DM1 were evaluated by Nine Hole Peg Test and re-evaluated at one week. Myotonia was not a limiting factor. The first test was compared with that performed by normal subjects (n = 28). Contextually, patients underwent handgrip and three-finger pinch assessments by handheld dynamometer. The Nine Hole Peg Test showed high intra-rater and inter-rater reliability in DM1 [ICC 0.86/0.83 for dominant and 0.90/0.88 for non-dominant hand, respectively]. Inverse correlation with handgrip and pinch strength values (r = -0.4; p < 0.01) and direct correlation with Muscular Impairment Rating Scale (r = 0.4; p < 0.01) were found for both DH and NDH. The test was able to differentiate severe DM1 patients, stratified by extent of muscle impairment, from mildly affected and normal controls, with a sensitivity of 97% and 95% for dominant hand and non-dominant hand, respectively (p < 0.0001). In conclusion, we showed that the Nine Hole Peg Test is a reliable, valid and sensitive test of dexterity in DM1, and that it can be considered as a candidate outcome measure to monitor natural history of disease and, possibly, therapeutic response in clinical trials.

Aquaporin 4 expression in human skeletal muscle fiber types: Short Reports

Introduction: Aquaporins (AQPs) are a family of transmembrane proteins involved in the maintenance of osmotic gradients. AQP4 is abundant in skeletal muscle, where it seems to be associated with glycolytic metabolism. We investigated the pattern of expression of AQP4 in normal human myofibers relative to the main forms of myosin heavy chain (MHC). Methods: Six normal human muscle biopsies were analyzed by double immunofluorescence for co‐expression of AQP4 and slow or fast MHC. Results: A high percentage (64–99%) of MHC‐fast positive fibers showed immunoreaction for AQP4. Immunoreactivity for AQP4 was also present in MHC‐slow positive fibers, but with a higher variability (5–72%) among biopsies. Discussion: The expression pattern of AQP4 in human myofibers is highly variable among different patients and cannot be predicted for single fibers depending on MHC type expression. Other factors, possibly related to muscle activity, may modulate AQP4 expression. Muscle Nerve 57: 856–859, 2018

Late-Onset Pompe Disease with Nemaline Bodies

Pompe disease is an autosomal recessive disorder characterized by deficiency of alpha-glucosidase, a lysosomal enzyme, which can lead to glycogen accumulation in skeletal muscle, heart, and nervous system. Clinical presentation is highly variable, with infantile and late-onset (LOPED) forms. Although muscle biopsy findings are rather stereotyped, atypical features have been described. A 52-year-old man without a family history of muscle disorders presented with slowly progressing upper and lower limb girdle weakness and hyperCKemia. At needle EMG, a diffuse neurogenic pattern was detected. Muscle biopsy showed a selective type 1 fiber atrophy with vacuoles of various sizes, filled with PAS and acid phosphatase positive material, confirmed to be glycogen by electron microscopy (EM). Many atrophic fibers contained foci of myofibrillar material recognized as nemaline bodies (NBs) at EM. Low level of alpha-glucosidase activity in blood and molecular genetic testing confirmed the diagnosis of late-onset Pompe disease (LOPED). Major causes of hereditary and acquired NB myopathy were ruled out. In conclusion, NBs represent a novel histological finding in LOPED and characterize the atypical presentation of our case.