Age of onset of neurological disease vs lifespan. Study on 97 cases for whom appropriate clinical information was available from the cohort of 181 patients originating from French hospitals. Each horizontal bar depicts one patient. The green color indicates the period during which the patient did not present neurological symptoms, irrespective of the presence or absence of preexisting systemic disease. Patients who died in their first days or months of life from systemic disease (n = 19) are not shown on this graph.