An infant with an unusual clinical presentation and course of Niemann-Pick disease type C (NPC) is described. The baby presented with severe pulmonary involvement and hepatosplenomegaly at the age of 3 months and died of respiratory failure at the age of 7 months. Cell hybridization studies revealed that the infant belonged to the rare genetic complementation group 2. To our knowledge, this is the third reported case with early-lethal pulmonary involvement in NPC. All three reported patients belong to the minor complementation group 2. An elder brother of the present case had also died at 6 weeks of age from NPC with severe pulmonary involvement. The two complementation groups cannot be distinguished from each other by clinical, cellular and biochemical criteria except for severe pulmonary involvement which may be characteristic of the second group.
Conclusion: NPC may present in early infancy with severe pulmonary involvement mimicking interstitial pneumonia. Such manifestation may be characteristic of the rare genetic complementation group 2.