Myotonic dystrophy type 2

Abstract

DM2 is present in a large number of families of northern European ancestry. Clinically, DM2 resembles adult-onset DM1, with myotonia, muscular dystrophy, cataracts, diabetes, testicular failure, hypogammaglobulinemia, and cardiac conduction defects. An important distinction is the lack of a congenital form of DM2. The clinical and molecular parallels between DM1 and DM2 indicate that the multisystemic features common to both diseases are caused by CUG or CCUG expansions expressed at the RNA level.

Anesthésie et dystrophie myotonique de type 2: une série de cas

“…17 The most frequent cardiac symptoms in DM2 patients are palpitation, intermittent tachycardia, and syncopal spells. 2 Conduction abnormalities and intraventricular and atrioventricular blocks were also described, 2 and were present in five of our patients. It is well established that sudden death can occur as a consequence of cardiac-conduction abnormalities in the DM1 patients.…”

“…1 Important distinctions of DM2 patients are the predominance of proximal muscle weakness and a milder disease course compared with DM1 patients. 1,2 Our DM2 patients tolerated commonly used anesthetic medications satisfactorily and exhibited normal response to a variety of muscle relaxants, including succinylcholine and several nondepolarizing relaxants. Also, reversing the effects of muscle relaxants with neostigmine was uneventful.…”

“…1,2 Though it shares some phenotypical features of classic or type 1 myotonic dystrophy (DM1), it is a genetically distinct disorder and recognized as a separate entity. [1][2][3][4][5][6] Anesthetic management of patients with DM2 has not been described, and it is unknown if these patients may have similar abnormal responses to anesthetic agents as do patients with DM1, for example, myotonic responses to succinylcholine, 7-10 increased sensitivity to nondepolarizing muscle relaxants, 3 myotonic responses to neostigmine, 3 or increased sensitivity to anesthetic agents. [11][12][13][14] To determine if patients with DM2 have similar atypical responses to anesthesia, we used the Mayo Clinic medical records database to identify patients with DM2 who underwent anesthesia, and we reviewed their anesthetic course.…”

Hairpin Structure-forming Propensity of the (CCTG·CAGG) Tetranucleotide Repeats Contributes to the Genetic Instability Associated with Myotonic Dystrophy Type 2

“…The characteristics of DM2 are very similar to those observed for DM1 and include myotonia, proximal weakness, frontal balding, cardiac arrhythmias, insulin-resistance associated diabetes mellitus, polychromatic cataracts, and infertility (2)(3)(4)(5)(6). The largest normal allele was found to contain 26 (CCTG⅐CAGG) repeats, whereas the repeats were expanded to 75-11,000 (average of 5,000 repeats) in patients (1).…”

Validation of Sensitivity and Specificity of Tetraplet-Primed PCR (TP-PCR) in the Molecular Diagnosis of Myotonic Dystrophy Type 2 (DM2)

“…9 An important element in the differential diagnosis with DM1 is the absence of congenital forms, which are observed only in DM1 families and which are characterized by polyhydramnios, reduced fetal movements, hypotonia, and respiratory distress at birth, with a high rate of perinatal deaths, developmental delay, and mental retardation. 10 Histological and immunohistochemical studies of DM2 muscles show the dystrophic phenotype with muscle atrophy, nuclear clumps, and type II fibers atrophy. 6,7 Atypical clinical presentations in DM2 have also been described, mimicking spinal muscular atrophy with adult onset, 11 fibromyalgia, 12 or with hyper-CK-emia as the sole clinical manifestation.…”