Ketogenic Diet in Niemann-Pick Type C: Insights From a Case Report.

Niemann-Pick disease type C (NPC) is a lysosomal storage disorder characterized by progressive neurological deterioration. Although there is no curative treatment, early initiation of miglustat, prior to significant neurological decline, may slow disease progression. This case report describes a patient whose initial symptoms emerged around age 9 and who was diagnosed with NPC at age 14 following gradual neurological decline. Despite being treated with miglustat, the patient's neurological symptoms worsened significantly. A high-ratio ketogenic diet (KD), based on fat to protein plus carbohydrate, was initiated as an adjunctive therapy. Following dietary modification, neurological findings stabilized. An initially abnormal electroencephalogram (EEG) normalized during follow-up. Due to significant weight loss, financial constraints and adherence difficulties, the KD ratio was reduced to 1:1 by the sixth month. At the time of the last evaluation, the patient had been maintained on the low-ratio KD for 4 years with continued adherence. The ketogenic diet is known to offer therapeutic benefits in various neurological disorders. In NPC patients treated with miglustat-particularly those experiencing seizures-a ketogenic diet may support neurological stabilization. A lower ratio KD may enhance long-term compliance.