Final answer:
Fasciculations are not typically found in congenital myotonic dystrophy as it affects muscle function differently, but they can sometimes be present in multifocal motor neuropathy which involves partial LMN pathology.
Step-by-step explanation:
Fasciculations, which are small involuntary muscle twitches, generally arise due to spontaneous activity from lower motor neurons (LMNs). Conditions that involve LMN pathology can result in fasciculations. However, in conditions like congenital myotonic dystrophy, fasciculations are typically not observed because this condition primarily affects muscle function through a different mechanism involving abnormal muscle relaxation.
On the other hand, multifocal motor neuropathy (MMN) is associated with partial LMN involvement where fasciculations can sometimes be present. MMN is characterized by progressive weakness without significant sensory loss, with conduction block as the main feature. Therefore, fasciculations may be absent in congenital myotonic dystrophy but can be found in multifocal motor neuropathy.