Two families from the U.S. and the U.K. have been determined to have a rare and previously unidentified inherited neuromuscular disorder. The new disease is the result of a genetic mutation that disrupts communication between nerves and muscles.
The discovery was made by an international team of scientists – including University of Rochester neurologist David Herrmann, M.B.B.Ch. – and appears in the American Journal of Human Genetics.
The findings were the result of a painstaking process of genetic sleuthing. There are a number of disorders that are related to the neuromuscular junction – the point at which the nerves pass chemical signals to the muscle cells.
In this instance, the family members had symptoms that resembled an acquired neuromuscular disorder – called Lambert-Eaton, which is usually brought about by certain cancers – but it had instead been passed from generation to generation.
The researchers created a profile of the protein coding genes for the families and found that they shared a defect in a part of the code responsible for creating the protein synaptotagmin 2 (SYT2). SYT2 plays a role in helping nerve cells identify fluctuations in calcium levels; changes that help tell the cells when to release the neurotransmitters that are responsible for sending signals between the nerve and muscle cells.
In these two families, the SYT2 mutation resulted in the disruption of communication and impairment of muscle control. You can read more about the study here.