Symptoms

The symptoms of Niemann- Pick Disease are all related to whichever organ they occur. Enlargement of the liver and spleen may cause reduced appetite, abdominal distension and pain as well as thrombocytopenia(thrombopenia for short) secondary to splenomegaly.

Sphingomyelin accumulation in the central nervous system (including the cerebellum) results in ataxia, slurring of speech (dysarthria) and discoordinated swallowing (dysphagia). Basal ganglia dysfunction causes abnormal posturing of the limbs, trunk and face (dystonia) and upper brainstem disease results in impaired voluntary rapid eye movements (supranuclear gaze palsy). More widespread disease involving the cerebral cortex and subcortical structures is responsible for gradual loss of intellectual abilities causing dementia and seizures

Sleep related disorders are also seen, including gelastic cataplexy (sudden loss of muscle tone associated with laughter), and sleep inversion (sleepiness during the day and wakefulness at night).