RCC1 neuropathy mimics childhood axonal Guillain–Barré syndrome with variable clinical severity and survival

We previously discovered RCC1 neuropathy in 24 patients. RCC1 neuropathy is a rare inherited condition where changes in the RCC1 gene cause otherwise healthy children to develop severe neurological difficulties in the days/weeks after catching an infection. Children are affected by muscle weakness, making it difficult to move, walk, and in severe cases it affects their breathing. Many patients with RCC1 neuropathy are diagnosed with a similar neurological disease called Guillain-Barré syndrome, but do not respond to immune treatment usually used by doctors. To develop effective treatments for RCC1 neuropathy, it is important to improve our understanding the underlying biological mechanisms involved in this condition. We identified changes in the RCC1 gene in 10 additional children from six families from around the world who developed neurological difficulties similar to those already described. Two children presented with neurological symptoms without a previous infection: one patient was affected from 2 months of age with severe neurological symptoms, in contrast, one patient developed very mild disease at the age of 5 years. Our analyses show that children whose symptoms develop before the age of 2 years were more likely to have a shorter survival time. In five of the newly identified families, we identified genetic changes which have not been seen before. The function of RCC1 is to provide energy to fuel the process of transporting different molecules into and out from the centre (nucleus) of each cell in the body. We discovered that the new genetic changes identified in patients reduced the stability of RCC1 at higher temperatures, and impaired its biological function, consistent with it causing neuropathy.