An international study led by Irish scientists has uncovered the mechanism behind a rare genetic disease that affects the brain.

Joubert syndrome is a brain disorder that affects around one in every 80,000 people. Symptoms can include problems with the formation of the mid-brain, breathing, balance and muscle control. It can also lead to kidney defects, obesity, bone malformation and blindness.

The condition is one of a number of disorders known as ‘ciliopathies'. These are caused by defects in a part of the cell called the cilium, which are hair-like structures found on the surface of most human cells.

These have a major role to play in sensory perception, such as odour detection, and cell-to-cell communication during embryo development.

According to scientists from University College Dublin (UCD), who helped lead this latest study, recent research has focused on the base of the cilium, where it attaches to the cell. This area is thought to act as a ‘gate', safeguarding the normal functioning of the cilium.

As part of their latest findings, the scientists have revealed a new gene associated with this ciliary gate. The gene is TMEM107 and the researchers have found that mutations in this gene cause Joubert syndrome.

The study involved scientists from UCD, Trinity College Dublin, France, the Netherlands and the UK.

"This research expands our understanding of how the cilium gate is organised and has implications for understanding ‘gates' in other parts of the cell. For patients with certain ciliopathies, it may be possible to design future intervention strategies to fine tune the gate, and therefore alleviate some of the progressive symptoms," commented the study's senior author, Dr Oliver Blacque, of UCD.

Also speaking about the findings, co-senior study author, Prof Christel Thauvin-Robinet, of Burgundy University in France, described the study as ‘another big step forward in our 10-year quest to identify the genes causing Joubert syndrome-associated disorders'.

Details of these findings are published in the journal, Nature Cell Biology.