Molecular basis of myotonic dystrophy: expansion of a trinucleotide (CTG) repeat at the 3′ end of a transcript encoding a protein kinase family member

JD Brook, ME McCurrach, HG Harley, AJ Buckler… - Cell, 1992 - cell.com
JD Brook, ME McCurrach, HG Harley, AJ Buckler, D Church, H Aburatani, K Hunter
Cell, 1992cell.com
Using positional cloning strategies, we have identified a CTG triplet repeat that undergoes
expansion in myotonic dystrophy patients. This sequence is highly variable in the normal
population. PCR analysis of the interval containing this repeat indicates that unaffected
individuals have between 5 and 27 copies. Myotonic dystrophy patients who are minimally
affected have at least 50 repeats, while more severely affected patients have expansion of
the repeat containing segment up to several kilobase pairs. The CTG repeat is transcribed …
Summary
Using positional cloning strategies, we have identified a CTG triplet repeat that undergoes expansion in myotonic dystrophy patients. This sequence is highly variable in the normal population. PCR analysis of the interval containing this repeat indicates that unaffected individuals have between 5 and 27 copies. Myotonic dystrophy patients who are minimally affected have at least 50 repeats, while more severely affected patients have expansion of the repeat containing segment up to several kilobase pairs. The CTG repeat is transcribed and is located in the 3’untranslated region of an mRNA that is expressed in tissues affected by myotonic dystrophy. This mRNA encodes a polypeptide that is a member of the protein kinase family.
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