המידע מתוך medicontext.co.il
By Steven Reinberg
WESTPORT, CT (Reuters Health) – Two new chromosome regions have been linked to autism, researchers report in the September issue of the American Journal of Human Genetics.
"We are trying to find the chromosome regions where susceptibility genes for autism lie," Dr. Anthony P Monaco from Oxford University, UK told Reuters Health. "We originally found an area on chromosome 7q and 16p. By enlarging the number of families in our study, we have now identified two new regions on chromosomes 2q and 17p," he said.
Dr. Monaco and Dr. Anthony J. Bailey from the Institute of Psychiatry in London, and colleagues from the International Molecular Genetic Study of Autism Consortium, looked for genetic links to autism among 152 sibling pairs with autism.
Among these individuals whole-genome screening was completed in 83, and 119 markers were genotyped in 13 candidate regions in an additional 69 sibling pairs.
LOD scores, which estimate the likelihood of two loci being near each other on a chromosome and are therefore likely to be inherited together, showed that there is strong evidence for the genetic link on chromosomes 2q and 7q, while the link for chromosomes 16p and 17p appear to be weaker.
Most significantly, at marker D2S2188 on chromosome 2, the multipoint maximum LOD score was 3.74, which increased to 4.80 when only sibling pairs that adhered to strict diagnostic criteria were included in the analysis. LOD scores of 3 or more indicate that two loci are close.
The second most significant link was found on chromosome 7, with a multipoint maximum LOD score of 3.20 at marker D7S477.
However, at D16S3102, chromosome 16 generated a multipoint maximum LOD score of 2.93 and chromosome 17 generated a multipoint maximum LOD score of 2.34 at HTTINT2, the researchers note.
"The exciting thing about this is that in complex genetics replication of results means a lot about how real the results are," Dr. Monaco said. "Our findings about chromosome 7q and chromosome 2q have been replicated by a number of groups."
"Now that we have narrowed areas of susceptibility down to small regions of a couple of chromosomes we should be able to identify the susceptibility genes and what variants in those genes increase a predisposition to autism," he added. Identifying these genes should lead to better diagnosis and, eventually, to better treatment.