When Genetic Diagnosis Is a Mid-Life Crisis: The Special Case of Late-Onset Disorders

In this chapter, we will use GNE myopathy as a doorway through which to discuss the broader challenges of diagnosing late-onset genetic disorders. Before diving into the complexities of GNE myopathy specifically, let’s define the scope of the topic. Late-onset genetic disorders are conditions that do not manifest during childhood, typically revealing their symptoms only after the age of 18 and, at times, only during middle age. In their classic form, these disorders remain under the radar for much of an individual’s life, allowing affected people to lead seemingly normal lives until the first signs appear.