MYOTONIC DYSTROPHY, 3RD EDITION

Abstract

MYOTONIC DYSTROPHY, 3rd edition By Peter S. Harper 2001. London: Harcourt Publishers Ltd Price £55. ISBN 0702021520 Professor Harper has written two widely acclaimed editions of a book on myotonic dystrophy, with the second edition published in 1989. Since then, identification of the causative triplet repeat has transformed diagnosis, genetic counselling and biological understanding of the disease. His computer has been busy with cutting and pasting for the new edition published in 2001. How does it look in 2002? In any genetic text there will almost inevitably be advances between the writing of the script and publication, making it impossible to optimize timing. The major advance since publication of the latest edition has been the discovery of the DM2/PROMM quadruplet expansion in the Zinc finger protein 9 ( ZNF9 ) gene on chromosome 3. This has implications for many aspects of myotonic dystrophy. There is already a better definition of the DM2/PROMM phenotype, which is close enough to classical myotonic dystrophy (DM1) to make it virtually indistinguishable clinically (except for the absence of congenital cases). The new data also has implications for the pathogenesis of myotonic dystrophy. For example, disruption of neighbouring genes to the DM1/DMPK expansion site would seem an unlikely disease mechanism if the same clinical effects were precipitated by an expansion elsewhere in the genome. With respect to DM2/PROMM the 2001 edition is, sadly, already obsolete. The first few pages of Chapter 3 concerning PROMM now serve to confuse, and the reader would do best to ignore this and seek out a more recent review, while sympathizing with the author on being outflanked by genetic advances. Fortunately, history does not change as fast as …