Intellectual disability and Down Syndrome – common genetics?


An investigation which aimed to understand the genetic basis for Down Syndrome has led to the identification of a gene which controls the formation of neural circuits in the brain.


New research led by Associate Professor Julian Heng, Head of the Brain Growth and Disease Laboratory at the Harry Perkins Institute of Medical Research, has identified a genetic factor which could be significant for intellectual disability as well as Down Syndrome.

Down Syndrome is recognised as the most prevalent form of intellectual disability, and results from an extra copy of all or parts of chromosome 21. Notably, Associate Professor Heng discovered that there were rare cases of children with abnormalities in chromosome 21 who were intellectually disabled, but did not display clinical features consistent with a positive diagnosis for Down Syndrome.

“We were puzzled by this, and thus predicted that genetic factors specifically for intellectual disability might be present on chromosome 21,” said Associate Professor Heng.

Guided by this notion, the team focussed its attention on a gene on chromosome 21, known as EURL (also known as C21ORF91). The research team went on to discover that EURL was critical for the production of appropriate numbers of neurons in the developing mammalian brain, as well as their ability to develop into functional brain circuits.

“Our work identifies EURL as a causative gene for intellectual disability in Down Syndrome, and indicates that disruptions to EURL are likely to alter the course of brain development and cause early onset mental conditions such as intellectual disability. Altogether, our data raises the possibility that treatments which correct the imbalance of gene products in brain cells, such as EURL, could lead to improvements in mental health and a better quality of life for individuals with certain forms of intellectual disability.” Associate Professor Heng said.

These findings were recently published in the Nature press journal, Scientific Reports (Li et al, Scientific Reports, 2016 Jul 11;6:29514. DOI: 10.1038/srep29514).


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