17 June 2013
ByAppeared in BioNews 709
An Introduction to the Genetics and Epigenetics of Human Disease
'An introduction to the Genetics and Epigenetics of Human Disease' does exactly what it says on the tin. A beginner's tour guide through genetics and epigenetics, it covers much of the fundamental biology behind genetic illness and gives a broad overview of some of the biggest challenges currently faced by researchers in the field. It does not assume any previous knowledge, and gives clear, concise summaries of key historical figures and theories, including a very useful glossary at the back.
However, one of the most interesting things about the booklet is how closely it is tied into the author's personal and family experiences of genetic diseases. Early in the book, the author, Professor Marcus Pembrey, clinical geneticist and founding chair of trustees at the Progress Educational Trust, discusses his sister's illness, an inheritable blood disorder called beta thalassaemia minor, which has obviously had a profound impact on his life and career.
He also refers to illnesses he has encountered professionally as a clinician – the extremely rare Angelman syndrome, and the relatively common Fragile X syndrome, known to be responsible for a large number of patients with learning disabilities.
These personal touches and anecdotes lift what could otherwise be a very straightforward primer into something much more vibrant. His reference to the worry of possibly passing faulty genes to his children echo the fears of thousands of parents around the world, and serves as a welcome reminder of just how many people could be helped by this research.
Another compelling aspect of the booklet is the excellent use of imagery. Clear explanations of the genetic issues behind common and well-known diseases are woven into the fabric of the narrative, explaining symptoms and onset at a cellular level. The analogies are beautifully clear, breaking biological processes down into a series of switches, vehicles and everyday interactions.
It was also refreshing to see animal research referred to in such a matter-of-fact tone. It is frequently omitted from introductory texts, and so to see it discussed as part of the standard introduction was a pleasant change, acknowledging that while it plays a key part in some strands of research, it does not define the field.
Like all good publications, the biggest problem is that it leaves you wanting more. Several casually mentioned issues could easily have become chapters in themselves – the effects of parental nutrition, some of the more rare genetic diseases, and even the Human Genome Project.
It would have been particularly interesting to have included a little more information on exactly how genes are sequenced, which would in turn help explain why this is still a relatively new and rapidly developing field. The Human Genome Project, and the battle to become the first to sequence a full genome, would have been a good insight into how the lay of the land for geneticists has changed over the last twenty years. This could also possibly have tied into the discussion about the current limitations of genomics, and the promise of personalised medicine.
The booklet is refreshingly honest about those limitations. At one point, the author states that 'DNA alone is not destiny', explaining the influences of lifestyle choices and environmental factors on a person's genome.
Similarly, it could have been interesting to briefly discuss the nature of 'risk' when talking about genetic disease, even to distinguish between relative and absolute. This is particularly relevant to the section about BRCA1 and BRCA2, which have recently received much discussion in the international press. A 90 percent chance of developing breast cancer is staggeringly high and very different to most media-quoted statistics, which often deal with relative risk. It may have been helpful to draw a line between the two.
However, these are minor points and do not detract from the fact that this is a wonderfully concise whistlestop tour of the most important parts of genetics. Overall, this booklet is highly recommended for anyone who would like a simple introduction to the basics of genetic disease, supported by a thoughtfully composed reading list that will help explain the ethics and practice of genetic research.