Download ment. The penultimate section on the origin of usually occur de novo

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416
Book reviews
in the field. It is based primarily on human material, of such de novo rearrangements are paternal in
reflecting the tremendous growth that has occurred origin. The last section in this book reflects on the
in this body of data during recent years. Structural significance of breakpoints in chromosome abnorchromosome abnormalities pose challenging prob- malities and contains a diverse and somewhat
lems for the cytogeneticist and the clinician alike. disjointed collection of nonetheless interesting
Balanced rearrangements can give rise to abnormal chapters, which include phenotype/karyotype
offspring and are a significant cause of spontaneous correlations in man and mouse, small deletion
abortion and infertility. Furthermore, acquired syndromes associated with Mendelian disorders, the
autosomal rearrangements are now recognised as a incidence and effects of mobile genetic elements,
major component of the neoplastic process and, cancer cytogenetics, and gene mapping.
This is an excellent, well presented book, bringing
as the nature of the associated molecular events
gradually unfolds, are becoming increasingly useful together a wealth of information that would otherin the diagnosis and management of many malignant wise only be available from a variety of quite
conditions. At the other end of the spectrum, the different sources. It should be essential reading for
role of autosomal rearrangements in promoting every cytogeneticist and it should prove very useful
population diversification and speciation, by creating for researchers, despite being slightly out of date. In
containing wide ranging material, it will no doubt, as
barriers to panmixia, has long been recognised.
The book is divided, rather arbitrarily perhaps, the editor indeed contends, contribute to the cross
into four sections. The first deals with the meiotic fertilisation of ideas within this field. The busy
consequences of balanced translocations, pericentric clinician, however, might find that a few of the
and paracentric inversions, and insertions. Both articles are peripheral to clinical interest and that
livebirth and amniocentesis statistics are examined much of the more valuable information on risk
and empirical models of risk for the production of assessment is impossible to access quickly.
viable unbalanced progeny are proposed. It appears
SELWYN H ROBERTS
that the identities of the chromosomes involved, the
length and nature of the segment in imbalance, the
effect of trisomy compared with monosomy, the
type of segregation, the pachytene configuration, Duchenne Muscular Dystrophy
the mode of ascertainment, and the sex of the Revised edition. Oxford Monographs on Medical
carrier can all influence the degree of risk. Regret- Genetics No 15. By Alan E H Emery. (Pp 317;
tably though, despite a degree of overlap in the £17.50.) Oxford: Oxford University Press. 1988.
subject matter of these chapters, a consensus view
on the relative importance of these risk factors does This revised paperback edition of Alan Emery's
not emerge. In the second section contributors excellent book on Duchenne muscular dystrophy
explore the effects of translocations in man, domestic contains an enlarged chapter on molecular pathology.
animals, and rodents on gametic selection, fertility, Here there is an account of finding submicroscopic
and reproductive loss. The potential scale of this deletions in 70% of patients with Duchenne or
problem is highlighted by the elegant technique of Becker muscular dystrophy, a discussion of germline
karyotyping human spermatozoa, which shows that mosaicism, or the presence of a microinversion in a
up to 77% of sperm from carriers of autosomal female to explain multiple cases born to non-carrier
rearrangements can have an unbalanced comple- parents, and a warning that such rare families must
ment. The penultimate section on the origin of produce caution when giving genetic advice. There
chromosome rearrangements treats the subject from is an account in this chapter of the isolation of
both evolutionary and aetiological standpoints. First, dystrophin with its implications for the pathogenesis
the importance of chromosome fusion and fission in of muscular dystrophy, but no mention of dystrophin
mammalian karyotypic diversification is evaluated, in the chapter on confirmation of the diagnosis.
then unbalanced structural abnormalities which These few useful additions do not warrant buying
usually occur de novo are examined; stable dicentrics, the revised edition as well as the first, but they
isochromosomes, rings, duplications, and the intri- ensure that the book remains a thoroughly sound,
guing and incorrectly named anomaly, inv dup(15), practical, and valuable monograph of widespread
are described in some detail. A fascinating study interest.
using heterochromatic variants shows that in a
SARAH BUNDEY
reversal of the situation in Down's syndrome 84%
Downloaded from http://jmg.bmj.com/ on May 13, 2017 - Published by group.bmj.com
Duchenne Muscular Dystrophy
Sarah Bundey
J Med Genet 1989 26: 416
doi: 10.1136/jmg.26.6.416
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