A 54-year-old woman was referred to hospital because of poor metabolic control. Clinical examination revealed marked acanthosis nigricans, and a striking lack of adipose tissue on the limbs, and excess fat deposits on the neck and face. She had been treated for diabetes since 2001 with high doses of insulin along with metformin. Clinical tests showed hypertriglyceridaemia with low high density lipoprotein (HDL) cholesterol, and cholestasis with mild cytolysis. Dunnigan syndrome (familial partial lipodystrophy type 2) was suspected and confirmed by molecular genetics. Pioglitazone was added to her treatment, and follow-up showed improvement of metabolic control 7 months after introducing pioglitazone, and improvement of insulin sensitivity 2 years later. Diabetes related to mutations of the lamin A/C gene is difficult to treat because of severe insulin resistance. Nevertheless, therapy with pioglitazone resulted in marked and sustained improvements in metabolic control and insulin sensitivity.