Niemann-Pick Disease (NPD) is a rare inherited metabolic disorder that affects the body's ability to metabolize fat. There are several types of NPD, each with a different genetic cause and varying symptoms. Some of the synonyms for NPD include Niemann-Pick Type A, Niemann-Pick Type B, Niemann-Pick Type C1, Niemann-Pick Type C2, and Niemann-Pick Disease Type D. NPD symptoms can range from mild to severe and may include an enlarged spleen and liver, developmental delays, and difficulty with coordination and movement. While there is currently no cure for NPD, treatments are available to manage symptoms and prolong life expectancy.