Linkage was shown between the myotonic dystrophy locus (DM) and a highly polymorphic AC repeat marker within the kallikrein (KLK1) locus (Z = 3.00, theta = 0.0). Linkage between KLK1 and the highly polymorphic AC repeat marker within the apolipoprotein C2 (APOC2) locus, which had been established in normal families, was confirmed in myotonic dystrophy families (Z = 4.37, theta = 0.11). These hi...

OBJECTIVE Examination of left ventricular function and conduction abnormalities in myotonic dystrophy. DESIGN Twelve patients (median age, 13.7 years) with myotonic dystrophy had detailed electrocardiography and echocardiography performed. Echocardiographic parameters were compared with body surface area (BSA) matched median normal values. RESULTS Fractional shortening was slightly reduced ...

BACKGROUND Animal experiments revealed that succinylcholine produced masseter muscle rigidity and activated myotonic discharges despite neuromuscular blockade with a nondepolarizing blocker. These results suggest that either succinylcholine or its metabolites might interfere directly with voltage-operated ion channels of the sarcolemma. The aim of this study was to examine effects of one produc...

Kennedy disease, a degenerative disorder characterized by androgen-dependent neuromuscular weakness, is caused by a CAG/glutamine tract expansion in the androgen receptor (Ar) gene. We developed a mouse model of Kennedy disease, using gene targeting to convert mouse androgen receptor (AR) to human sequence while introducing 113 glutamines. AR113Q mice developed hormone and glutamine length-depe...

Mutations within CLCN1, the gene encoding the major skeletal muscle chloride channel, cause either dominant Thomsen disease or recessive Becker-type myotonia, which are sometimes difficult to discriminate, because of reduced penetrance or lower clinical expressivity in females. We screened DNA of six unrelated Becker patients and found four novel CLCN1 mutations (Gln-74-Stop, Tyr-150-Cys, Tyr-2...

Isolated fibre bundles from myotonic human skeletal muscle showed after-contractions and spontaneous mechanical activity. The K+ channel openers cromakalim (10-100 mumols/l) and EMD 52962 (1-10 mumols/l) completely suppressed these abnormalities in mechanical activity. Voltage-clamp experiments revealed that cromakalim (100 mumols/l) increased the membrane K+ conductance of isolated, non-myoton...

Three cases of androgen-dependent disease in females with myotonic dystrophy are described. Serum androgens in individuals affected by myotonic dystrophy are known to be lower on average than in normal controls. Despite this these three females developed diseases that are androgen dependent, including acne, hidradenitis suppurativa, androgenetic alopecia and keratosis pilaris. These cases suppo...

Daytime sleepiness is common in myotonic dystrophy and might be attributed to disturbed nocturnal breathing. Seventeen out of 22 patients complained of excessive daytime sleepiness, resembling "idiopathic hypersomnolence". Sleep apnoea might have contributed to daytime sleepiness in only three of 17 patients. Treatment with the central stimulant methylphenidate produced sustained benefit in sev...

We present the case of a 42-year-old woman with myotonic dystrophy and thymoma. She was treated with combination chemotherapy followed by external beam radiation, and remains in remission 19 months after thymoma was diagnosed. The myotonic dystrophy is unchanged. Only six cases of this nature have been reported in the literature, and this patient is the first to be successfully treated with com...

Myotonic dystrophy type 1 or Steinert’s disease is the most common form of adult muscular dystrophy affecting multiple systems with a wide spectrum of phenotypes. This paper focuses on the different methods to diagnose myotonic dystrophy type 1 that have been used over the years and the various modifications that have been made to the previous diagnostics. The different diagnostic assays and th...