Neurophakomatoses

Abstract

The term phakomatosis, from the Greek root phakos, meaning lens or spot, was first used in 1920 to describe a group of multisystem disorders with common neuro-oculocutaneous findings. Each condition is caused by distinct genetic defects, with some overlap in terms of protein function. They share pathogenetic mechanisms in dysfunction of a tumour suppressor gene. This chapter details four of the phakomatoses seen in practice—neurofibromatosis types 1 and 2, tuberous sclerosis complex, and von Hippel-Lindau—paying attention to their neurological sequelae and impact on neurosurgical practice. For each condition, the epidemiology, genetics, diagnostic criteria, screening, clinical features, management, and controversy will be reviewed, with an accompanying illustrative case.