TY - JOUR A1 - Pluta, Natalie A1 - Hoffjan, Sabine A1 - Zimmer, Frederic A1 - Köhler, Cornelia A1 - Lücke, Thomas A1 - Mohr, Jennifer A1 - Vorgerd, Matthias A1 - Nguyen, Hoa Huu Phuc A1 - Atlan, David A1 - Wolf, Beat A1 - Zaum, Ann-Kathrin A1 - Rost, Simone T1 - Homozygous inversion on chromosome 13 involving SGCG detected by short read whole genome sequencing in a patient suffering from limb-girdle muscular dystrophy JF - Genes N2 - New techniques in molecular genetic diagnostics now allow for accurate diagnosis in a large proportion of patients with muscular diseases. Nevertheless, many patients remain unsolved, although the clinical history and/or the muscle biopsy give a clear indication of the involved genes. In many cases, there is a strong suspicion that the cause must lie in unexplored gene areas, such as deep-intronic or other non-coding regions. In order to find these changes, next-generation sequencing (NGS) methods are constantly evolving, making it possible to sequence entire genomes to reveal these previously uninvestigated regions. Here, we present a young woman who was strongly suspected of having a so far genetically unsolved sarcoglycanopathy based on her clinical history and muscle biopsy. Using short read whole genome sequencing (WGS), a homozygous inversion on chromosome 13 involving SGCG and LINC00621 was detected. The breakpoint in intron 2 of SGCG led to the absence of γ-sarcoglycan, resulting in the manifestation of autosomal recessive limb-girdle muscular dystrophy 5 (LGMDR5) in the young woman. KW - inversion KW - sarcoglycanopathy KW - whole genome sequencing (WGS) KW - next generation sequencing (NGS) KW - LGMDR5 KW - muscle disease KW - genetic diagnostics Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288122 SN - 2073-4425 VL - 13 IS - 10 ER - TY - JOUR A1 - Hoppe, Kerstin A1 - Sartorius, Tina A1 - Chaiklieng, Sunisa A1 - Wietzorrek, Georg A1 - Ruth, Peter A1 - Jurkat-Rott, Karin A1 - Wearing, Scott A1 - Lehmann-Horn, Frank A1 - Klingler, Werner T1 - Paxilline Prevents the Onset of Myotonic Stiffness in Pharmacologically Induced Myotonia: A Preclinical Investigation JF - Frontiers in Physiology N2 - Reduced Cl\(^{-}\) conductance causes inhibited muscle relaxation after forceful voluntary contraction due to muscle membrane hyperexcitability. This represents the pathomechanism of myotonia congenita. Due to the prevailing data suggesting that an increased potassium level is a main contributor, we studied the effect of a modulator of a big conductance Ca\(^{2+}\)- and voltage-activated K\(^{+}\) channels (BK) modulator on contraction and relaxation of slow- and high-twitch muscle specimen before and after the pharmacological induction of myotonia. Human and murine muscle specimens (wild-type and BK\(^{-/-}\)) were exposed to anthracene-9-carboxylic acid (9-AC) to inhibit CLC-1 chloride channels and to induce myotonia in-vitro. Functional effects of BK-channel activation and blockade were investigated by exposing slow-twitch (soleus) and fast-twitch (extensor digitorum longus) murine muscle specimens or human musculus vastus lateralis to an activator (NS1608) and a blocker (Paxilline), respectively. Muscle-twitch force and relaxation times (T\(_{90/10}\)) were monitored. Compared to wild type, fast-twitch muscle specimen of BK\(^{-/-}\) mice resulted in a significantly decreased T\(_{90/10}\) in presence of 9-AC. Paxilline significantly shortened T\(_{90/10}\) of murine slow- and fast-twitch muscles as well as human vastus lateralis muscle. Moreover, twitch force was significantly reduced after application of Paxilline in myotonic muscle. NS1608 had opposite effects to Paxilline and aggravated the onset of myotonic activity by prolongation of T\(_{90/10}\). The currently used standard therapy for myotonia is, in some individuals, not very effective. This in vitro study demonstrated that a BK channel blocker lowers myotonic stiffness and thus highlights its potential therapeutic option in myotonia congenital (MC). KW - paxilline KW - NS1608 KW - repetitive firing KW - myotonia congenita KW - muscle disease KW - BK channel Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218152 VL - 11 ER -