LMBBS Laurence Moon Bardet Biedl Society

RNIB - Insight magazine

Looking for LMBBS

Professor Philip Beales is Professor of Medical and Molecular Genetics at the Institute of Child Health and has been researching LMBBS for many years. He reveals some of the great strides, as well as the limitations, in scientific knowledge of this highly complex condition.

What causes weight problems in LMBBS?
There is no single cause or cure for obesity. One aspect is that the appetite-regulating cells in the hypothalamus area of the brain are affected. The brain doesn’t register that the person is satisfied and so they have a tendency to overeat. Another factor is that people with LMBBS are less likely to move around and be active. This also has a genetic base, possibly resulting from changes to the neural network during an embryo’s development.

Because of the influence of their genes, it can be much harder for people with LMBBS to lose weight. However the two young people in this article prove that it really is possible to get fit with a combination of diet and excercise. Other approaches that can be used in combination include behavioural therapy and in some cases medication.

What causes the sight problems?
We now know that cilia are at the root of the rod-cone dystrophy. All cells in the body have cilia, which are hair-like projections from the outside wall. They are often adapted to perform special functions, such as the beating cilia in the lungs. The photoreceptor cells in the retina have highly evolved cilia which transmit information about light to the brain.

During this process molecules of protein carry chemical messengers towards the brain and remove the waste products afterwards. In LMBBS the gene mutations mean that faulty proteins are created which are unable to carry out their functions correctly. One hypothesis is that this leads to the photoreceptors becoming overwhelmed and damaged by the waste products in the cells. Eventually the cells can stop working altogether leading to sight loss.

What happens as children grow up?
Because it is such a complex condition it needs to be viewed as an emerging pattern. There will be different problems to be faced over time, affecting many parts of the body. There is no one method of treatment and no single way of dealing with the psychological and practical issues. As yet it is not possible to predict the severity of future problems, such as kidney failure, from the type of genes a person has.

Knowledge is power for families
Families can access information and support through the LMBBS Society and other organisations dealing with the range of problems children may face. The LMBBS Society allows parents to meet and lets families help to increase scientific knowledge by taking part in research. It was in fact research carried out through the Society that helped produce the first ever set of diagnostic criteria which are now in use.

LMBBS Annual Family Conference takes place on 25-27 April 2008. Early booking is recommended. For further information please contact chris.humphreys4@ntlworld.com