Multiple symmetric lipomatosis: an unusual cause of childhood obesity and mental retardation.

Multiple symmetric lipomatosis (MSL), also known as Launois-Bensaude syndrome or Madelung's disease, is a rare disorder predominantly seen in middle-aged male patients. The disorder is characterized by large subcutaneous fat masses distributed around the neck, shoulders, and other parts of the trunk, often associated with nervous system abnormalities. A close relationship to alcoholism, metabolic disturbances and malignant tumours has been observed. Until now, MSL has only been described in adults. We report on the first two children, a 9-year-old girl and a 13-year-old boy, with the characteristic clinical findings of MSL. The girl presented with severe obesity, developmental delay, mild mental retardation, peripheral neuropathy, and latent hypothyroidism. In addition, she had elevated lactate concentrations in blood and cerebral spinal fluid suggesting mitochondrial dysfunction. Biochemical analyses of muscle showed a respiratory chain complex II deficiency. The boy suffered from severe obesity, mild mental retardation and insulin resistant diabetes mellitus. In both children, analyses of the mitochondrial genome did not reveal major deletions nor the MERRF 8344 point mutation. MSL seems to be a new neurometabolic disorder with heterogeneous clinical expression whose pathogenesis is still unknown.