A molecular protocol for diagnosing myotonic dystrophy

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 41; no. 1; pp. 69 - 72
• Main Authors: Guida, M, Marger, RS, Papp, AC, Snyder, PJ, Sedra, MS, Kissel, JT, Mendell, JR, Prior, TW
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01.01.1995; American Association for Clinical Chemistry
• Subjects: Adult; Aged; Alleles; Base Sequence; Biological and medical sciences; Blotting, Southern; Diseases of striated muscles. Neuromuscular diseases; DNA Probes; Female; Humans; Male; Medical sciences; Middle Aged; Molecular Sequence Data; Myotonic Dystrophy - diagnosis; Myotonic Dystrophy - genetics; Neurology; Pedigree; Phenotype; Polymerase Chain Reaction; Repetitive Sequences, Nucleic Acid; Human; Polymerase chain reaction; Neuromuscular diseases; Nervous system diseases; Allele; Myotonic dystrophy; Myotonia; Clinical biology; F19-Chromosome; Diagnosis; Southern blotting; Genetic disease
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1093/clinchem/41.1.69

Myotonic dystrophy (DM) is an autosomal dominant genetic disease caused by an unstable CTG repeat sequence in the 3' untranslated region of the myotonin protein kinase gene. The CTG repeat is present 5-30 times in the normal population, whereas DM patients have CTG expansions of 50 to several thousand repeats. The age of onset of the disorder and the severity of the phenotype is roughly correlated with the size of the CTG expansion. We developed a molecular protocol for the diagnosis of DM based on an initial polymerase chain reaction screen to detect normal-sized alleles and small expansions, followed by an improved Southern protocol to detect larger expansions.