Genes in Brain Disorder Diagnosis: What methods should researchers be using?

The brain is the most important organ, the centre for all human function; therefore it would make sense that it is so widely studied. However, whilst being the most important, it is also highly complex, which makes it quite complicated in biomedical research. There is very little understanding of the functions of the brain, especially the genesis of the high order brain functions, which are central to brain disorders such as self-awareness, perception, thought and mood. Some researchers are sceptical about the use of genetics in the diagnosis pathway; however there is increasing evidence that genes are involved. There have been numerous amounts of gene studies conducted in relation to the brain, including many different approaches, old and new. Recent reviews have provided conflicting arguments, as to which approaches are favourable. A study which has been successful in identifying the genes related to Mental Retardation has been the study of balanced translocations and other chromosomal abnormalities. While these studies may not significantly contribute to brain disorders, studies of rare copying number variants (smaller chromosomal abnormalities) have increased the understanding of disease mechanisms for schizophrenia, autism, epilepsy, as well as mental retardation.

From numerous studies, it appears that for one disorder, numerous loci are involved which further complicates the understanding of the mechanisms. Due to the lack of specific information, researchers rely on candidate gene approach. However, with genome wide association (GWA) technology, the reliance of the approach has been diminished. It is expected that in the next few years, with advancement in gene sequencing, a further depletion in candidate gene approach will arise. GWA studies that use a larger sample should provide a better alternative for the candidate gene approach. There are several difficulties in the diagnosis of brain disorders, but recent reviews suggest that they can certainly be overcome. No single approach can be used for all brain disorders therefore it is important to employ all genetic tools, old and new. While there are still many gaps in the understanding of the brain, even partial glimpses of functions can amount to major advances on current pathophysiology knowledge, which in turn, can facilitate a higher standard of patient care.

Article Link: http://www.springerlink.com/content/g1070h252t881164/?p=c4bd58053de245c28128ddc3d13c8e3e&pi=0

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Human Genet. doi:10.1007/s00439-009-0695-9

Franke B, Neale BM, Faraone SV (2009) Genome-wide association
studies in ADHD. Human Genet. doi:10.1007/s00439-009-0663-4