A Novel Heterozygous Mutation in Peroxisome Proliferator-Activated Receptor-γ Gene in a Patient with Familial Partial Lipodystrophy

Abstract

Familial partial lipodystrophies (FPL) are a heterogeneous group of genetic disorders characterized by marked loss of subcutaneous (sc) fat from the extremities. Affected individuals show an increased preponderance of insulin resistance, diabetes mellitus and dyslipidemia. Recently, lamin A/C gene mutations were found in patients with FPL, Dunnigan variety. However, the genetic basis of other phenotypes remains unknown. We studied peroxisome proliferator-activated receptor-gamma (PPARgamma) gene as a candidate gene in seven FPL patients who did not appear to have Dunnigan variety. Analysis of the coding region of PPARG revealed C to T heterozygous mutation at nucleotide 1273 in exon 6 which changes a highly conserved residue, arginine at position 425 to cysteine (R425C) in the patient FX200.21. The patient is a 64-year-old nonHispanic white woman who developed diabetes mellitus and hypertriglyceridemia at age 32 years and lipodystrophy of the extremities and face at age 50 years. She also had hirsutism. Anthropometry and whole body magnetic resonance imaging revealed marked loss of sc fat particularly from the extremities but sc truncal fat was slightly increased. None of the four unaffected family members harbored the mutation. We conclude that heterozygous, R425C, mutation in PPARG could be the molecular basis for one of the familial partial lipodystrophy phenotypes.