@article{MairBiskupKressetal.2020, author = {Mair, Dorothea and Biskup, Saskia and Kress, Wolfram and Abicht, Angela and Br{\"u}ck, Wolfgang and Zechel, Sabrina and Knop, Karl Christian and Koenig, Fatima Barbara and Tey, Shelisa and Nikolin, Stefan and Eggermann, Katja and Kurth, Ingo and Ferbert, Andreas and Weis, Joachim}, title = {Differential diagnosis of vacuolar myopathies in the NGS era}, series = {Brain Pathology}, volume = {30}, journal = {Brain Pathology}, number = {5}, doi = {10.1111/bpa.12864}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-216048}, pages = {877 -- 896}, year = {2020}, abstract = {Altered autophagy accompanied by abnormal autophagic (rimmed) vacuoles detectable by light and electron microscopy is a common denominator of many familial and sporadic non-inflammatory muscle diseases. Even in the era of next generation sequencing (NGS), late-onset vacuolar myopathies remain a diagnostic challenge. We identified 32 adult vacuolar myopathy patients from 30 unrelated families, studied their clinical, histopathological and ultrastructural characteristics and performed genetic testing in index patients and relatives using Sanger sequencing and NGS including whole exome sequencing (WES). We established a molecular genetic diagnosis in 17 patients. Pathogenic mutations were found in genes typically linked to vacuolar myopathy (GNE, LDB3/ZASP, MYOT, DES and GAA), but also in genes not regularly associated with severely altered autophagy (FKRP, DYSF, CAV3, COL6A2, GYG1 and TRIM32) and in the digenic facioscapulohumeral muscular dystrophy 2. Characteristic histopathological features including distinct patterns of myofibrillar disarray and evidence of exocytosis proved to be helpful to distinguish causes of vacuolar myopathies. Biopsy validated the pathogenicity of the novel mutations p.(Phe55*) and p.(Arg216*) in GYG1 and of the p.(Leu156Pro) TRIM32 mutation combined with compound heterozygous deletion of exon 2 of TRIM32 and expanded the phenotype of Ala93Thr-caveolinopathy and of limb-girdle muscular dystrophy 2i caused by FKRP mutation. In 15 patients no causal variants were detected by Sanger sequencing and NGS panel analysis. In 12 of these cases, WES was performed, but did not yield any definite mutation or likely candidate gene. In one of these patients with a family history of muscle weakness, the vacuolar myopathy was eventually linked to chloroquine therapy. Our study illustrates the wide phenotypic and genotypic heterogeneity of vacuolar myopathies and validates the role of histopathology in assessing the pathogenicity of novel mutations detected by NGS. In a sizable portion of vacuolar myopathy cases, it remains to be shown whether the cause is hereditary or degenerative.}, language = {en} } @article{EgenolfAltenschildescheKressetal.2021, author = {Egenolf, Nadine and Altenschildesche, Caren Meyer zu and Kreß, Luisa and Eggermann, Katja and Namer, Barbara and Gross, Franziska and Klitsch, Alexander and Malzacher, Tobias and Kampik, Daniel and Malik, Rayaz A. and Kurth, Ingo and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan}, title = {Diagnosing small fiber neuropathy in clinical practice: a deep phenotyping study}, series = {Therapeutic Advances in Neurological Disorders}, volume = {14}, journal = {Therapeutic Advances in Neurological Disorders}, issn = {1756-2864}, doi = {10.1177/17562864211004318}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232019}, year = {2021}, abstract = {Background and aims: Small fiber neuropathy (SFN) is increasingly suspected in patients with pain of uncertain origin, and making the diagnosis remains a challenge lacking a diagnostic gold standard. Methods: In this case-control study, we prospectively recruited 86 patients with a medical history and clinical phenotype suggestive of SFN. Patients underwent neurological examination, quantitative sensory testing (QST), and distal and proximal skin punch biopsy, and were tested for pain-associated gene loci. Fifty-five of these patients additionally underwent pain-related evoked potentials (PREP), corneal confocal microscopy (CCM), and a quantitative sudomotor axon reflex test (QSART). Results: Abnormal distal intraepidermal nerve fiber density (IENFD) (60/86, 70\%) and neurological examination (53/86, 62\%) most frequently reflected small fiber disease. Adding CCM and/or PREP further increased the number of patients with small fiber impairment to 47/55 (85\%). Genetic testing revealed potentially pathogenic gene variants in 14/86 (16\%) index patients. QST, QSART, and proximal IENFD were of lower impact. Conclusion: We propose to diagnose SFN primarily based on the results of neurological examination and distal IENFD, with more detailed phenotyping in specialized centers.}, language = {en} }