Ten-year improvement of insulin resistance and growth with recombinant human insulin-like growth factor 1 in a patient with insulin receptor mutations resulting in leprechaunism.

AIM: Leprechaunism, a rare genetic disease resulting from mutations in two alleles of the insulin receptor gene, is characterized by severe insulin resistance, retarded growth and, usually, premature death. The ability of treatment with recombinant human insulin-like growth factor 1 (rhIGF1) to improve metabolic and clinical parameters in the long-term is still controversial. METHODS: Mutations were looked for in the insulin receptor gene of a four-month-old female baby with leprechaunism. The patient's skin fibroblasts were analyzed for response to insulin and IGF1. At the clinical level, the very long-term effects of treatment with rhIGF1/rhIGFBP3 were evaluated by clinical and metabolic parameters. RESULTS: The patient's diagnosis was based on compound heterozygous mutations in two alleles of the insulin receptor gene, thus confirming leprechaunism. Cultured fibroblasts showed a decreased number of insulin receptors and were insulin-resistant. However, IGF1 was able to stimulate IGF1 receptor signalling, suggesting possible activation of a salvage pathway. Treatment with IGF1/IGFBP3 for 8.7 years, then IGF1 for 2 years, resulted in normalization of circulating levels of IGF1 and IGFBP3. Large daily variations in glycaemia and insulinaemia persisted, but mean glycaemia decreased. Regarding growth, the patient's BMI Z score normalized and length/height score improved. Our patient presented normal neurological development and academic achievement. The treatment was free of adverse effects. CONCLUSION: Our results provide evidence that rhIGF1 with and without rhIGFBP3 can prevent fatal outcomes, and improve growth and metabolic parameters, for more than 10 years in a patient with leprechaunism. Long-term rhIGF1 for severe insulin resistance syndrome should be considered.

Nuclear envelope-related lipodystrophies.

Several alterations in nuclear envelope proteins building up the lamina meshwork beneath the inner nuclear membrane (mutations in lamins A/C, alterations of prelamin-A maturation, lamin B mutations or deregulation) have been shown to be responsible for or associated to human lipodystrophic syndromes. Lipodystrophic syndromes are rare and heterogeneous diseases, either genetic or acquired, characterized by generalized or partial fat atrophy associated with metabolic complications comprising insulin-resistant diabetes, dyslipidemia, and non-alcoholic fatty liver disease. Recent advances in the molecular genetics of different types of lipodystrophies generally pointed to primary adipocyte alterations leading to impaired adipogenesis and/or deregulation of the adipocyte lipid droplet. However, the precise mechanisms linking nuclear envelope abnormalities to lipodystrophies remain largely unknown. The phenotype of nuclear envelope-linked lipodystrophies ranges from the typical familial partial lipodystrophy of the Dunnigan type (FPLD2), due to heterozygous substitutions of the 482nd arginine of lamins A/C, to complex diseases that can combine lipodystrophy, metabolic complications, muscular or cardiac alterations and/or signs of accelerated aging. In this review we present the clinical, tissular and cellular characteristics of the nuclear envelope-linked lipodystrophies, as well as their hypothetical pathophysiological mechanisms.