PNPLA2 mutation: a paediatric case with early onset but indolent course.

Neutral lipid storage disease (NLSD) due to PNPLA2 mutation is a rare disorder with a severe muscular and cardiac outcome. All but one reported cases have been diagnosed during adulthood. It is thus ordinarily distinguished from Chanarin-Dorfman syndrome, a paediatric NLSD with a more widespread symptomatology. We report the case of a young child incidentally diagnosed with significant and persistent hyperCKemia. At 3 years, muscle biopsy showed marked lipid storage. A homozygous mutation in PNPLA2 was found. Fourteen years later, the noticeable outcome is the absence of muscle weakness at rest, a normal muscular MRI, and no cardiac involvement. Yet the patient exhibits some systemic features, notably hearing loss. This paediatric case of NLSD with myopathy indicates that important lipid accumulation may occur very early in the absence of patent clinical and imaging muscle involvement. Furthermore, PNPLA2 mutations may be associated with multisystem features more frequently encountered in Chanarin-Dorfman syndrome.