Early onset of cardiomyopathy and primary prevention of sudden death in X-linked Emery-Dreifuss muscular dystrophy.

We report the case of 14-year-old boy with X-linked Emery-Dreifuss muscular dystrophy who developed sick sinus syndrome and required placement of an implantable intracardiac cardioverter-defibrillator (ICD) to prevent sudden death. He demonstrated no significant risk factors for sudden death such as depressed left ventricular ejection fraction, or spontaneous or inducible ventricular tachycardia. One month after implantation, the patient experienced one appropriate ICD discharge.

Corneal thickness and endothelial cell characteristics in patients with myotonic dystrophy.

PURPOSE: To compare the characteristics of the endothelial cells of patients with myotonic dystrophy and those of normal subjects to determine if thicker corneas in patients with myotonic dystrophy are the result of their having abnormal endothelial cells leading to corneal edema. DESIGN: Prospective, comparative case series. PARTICIPANTS: Fifty-two eyes of patients with myotonic dystrophy and 52 eyes of normal age- and gender-matched subjects. METHODS: Central corneal thickness (CCT) and endothelial cell counts and shape were measured with an SP 3000P specular microscope (Topcon, Tokyo, Japan) in patients with myotonic dystrophy and were compared with those of age- and gender-matched healthy subjects. MAIN OUTCOME MEASURES: Central corneal thickness, endothelial cell counts, pleomorphism, and coefficient of variation (CoV). RESULTS: In patients with myotonic dystrophy, the mean+/-standard deviation CCT measurement was 533+/-38 microm; the mean+/-standard deviation cell count was 2601+/-365 cell/mm(2); and the mean+/-standard deviation CoV was 23.3+/-4.4 (P<0.001). The mean+/-standard deviation pleomorphism was 64.4+/-8.4%. In healthy subjects, the mean+/-standard deviation CCT measurement was 514+/-27 microm (P = 0.002); the mean+/-standard deviation cell count was 2649+/-363 cell/mm(2) (P = 0.48); the mean+/-standard deviation CoV was 27.6+/-5.5 (P<0.001); and the mean+/-standard deviation pleomorphism was 61.1+/-8.6% (P = 0.04). CONCLUSIONS: Thicker corneas found in patients with myotonic dystrophy are not related to endothelial number or appearance as assessed in this study.

Log-PCR: a new tool for immediate and cost-effective diagnosis of up to 85% of dystrophin gene mutations.

BACKGROUND: Duchenne (DMD) and Becker (BMD) muscular dystrophies are caused by mutations in the dystrophin gene. Despite the progress in the technologies of mutation detection, the disease of one third of patients escapes molecular definition because the labor and expense involved has precluded analyzing the entire gene. Novel techniques with higher detection rates, such as multiplex ligation-dependent probe amplification and multiplex amplifiable probe hybridization, have been introduced. METHODS: We approached the challenge of multiplexing by modifying the PCR chemistry. We set up a rapid protocol that analyzes all dystrophin exons and flanking introns (57.5 kb). We grouped exons according to their effect on the reading frame and ran 2 PCR reactions for DMD mutations and 2 reactions for BMD mutations under the same conditions. The PCR products are evenly spaced logarithmically on the gel (Log-PCR) in an order that reproduces their chromosomal locations. This strategy enables both simultaneous mapping of all the mutation borders and distinguishing between DMD and BMD. As a proof of principle, we reexamined samples from 506 patients who had received a DMD or BMD diagnosis. RESULTS: We observed gross rearrangements in 428 of the patients (84.6%; 74.5% deletions and 10.1% duplications). We also recognized a much broader spectrum of mutations and identified 14.6% additional cases. CONCLUSIONS: This study is the first exhaustive investigation of this subject and has made possible the development of a cost-effective test for diagnosing a larger proportion of cases. The benefit of this approach may allow more focused efforts for discovering small or deep-intronic mutations among the few remaining undiagnosed cases. The same protocol can be extended to set up Log-PCRs for other high-throughput applications.

Retinoic acid inhibits the growth of bone marrow mesenchymal stem cells and induces p27Kip1 and p16INK4A up-regulation.

The importance of bone marrow mesenchymal stem cells in hemopoiesis has been definitely demonstrated. Thus, their impairment might cause profound alteration on production and maturation of blood cells. In the present paper, we investigated, for the first time, the effect of retinoic acid, an important antileukemic molecule, on the proliferation of primary cultures of human bone marrow mesenchymal stem cells. We demonstrated that retinoic acid, at a pharmacological concentration, hampers strongly the growth of the cells, without inducing osteoblastic differentiation. The analysis of cell division cycle machinery showed that the antiproliferative effect is associated with (i) the up-regulation of two cyclin-dependent kinase inhibitors, namely p27Kip1 and p16INK4A, and (ii) the down-regulation of cyclin-dependent kinase 2 activity and pRB phosphorylation. The reported findings represent novel insights into the antileukemic effects of the drug and contribute in clarifying the molecular mechanism of its pharmacological activity.