Exome sequencing enables the discovery of a new gene involved in the disease

A novel technique that speeds up the examination of the genome (genetic make-up) of people has recently become available: before analyzing the sequence of nucleic acids of DNA (the letters of the genetic code) it identifies the Exome i.e. the part of DNA which is actually used to make proteins that become the building blocks of our body.  This increases the probability of finding important mutations of genes (the functional units that code one or more proteins)

A group of international researchers, using exome sequencing to analyze the DNA of a few rare families with hereditary Parkinson’s disease (PD), have found a new gene, called VPS35, which is involved in PD.  The mutation was sought in 4326 patients and  3309 control subjects without the disease:  mutations of the gene were found in a few families with hereditary PD and in none of the healthy controls.

The VPS gene is dominant (it is sufficient to have one mutated copy of the gene to develop the disease), but its penetrance is incomplete (not all the people with this mutation develop the disease).

The gene is involved in old protein recycling i.e. in their transport in endosomes to the Golgi apparatus, which can be considered to be a storehouse of the cell.  This discovery gives further credence to the theory that PD is due to a problem connected to old protein disposal