Neurodevelopmental brainstem syndromes.

Prenatal development of the brainstem is a meticulously orchestrated process, reliant on the coordinated activity of numerous genes and environmental cues. Disruption of this process, whether by genetic mutations or acquired insults during fetal development, can lead to brainstem dysfunction, characterized by a spectrum of clinical manifestations including cranial nerve palsies, cognitive and behavioral deficits, sensory and motor impairments, dysautonomia, and respiratory insufficiency. This chapter is dedicated to disorders primarily involving the brainstem and/or cranial nerves. It provides insights into the prenatal development of the brainstem, elucidates the clinical presentations associated with developmental disruptions, and offers an updated perspective on the genetic and acquired brainstem disorders. The umbrella term "brainstem dysgenesis" is employed herein to encompass all disorders stemming from aberrant brainstem development during embryogenesis. Given the phenotypic heterogeneity observed in brainstem dysgenesis, the identification of characteristic phenotypic patterns linked to acquired insults or inherited conditions is paramount. Such recognition facilitates accurate diagnosis, genetic counseling, prognostication, and the formulation of tailored care and therapeutic strategies.