Primary Outcome Measures:
- Weight [ Time Frame: Before and every 6 months after treatment is initiated, during 5 years ] [ Designated as safety issue: Yes ]
Secondary Outcome Measures:
- Endocrine parameters [ Time Frame: Before and every 6 months after treatment is initiated, during 5 years ] [ Designated as safety issue: Yes ]
- Bone mineral density [ Time Frame: Before and every 6 months after treatment is initiated, during 5 years ] [ Designated as safety issue: Yes ]
- Immune function [ Time Frame: Before and every 6 months after treatment is initiated, during 5 years ] [ Designated as safety issue: Yes ]
The proposed study of the treatment of a child with congenital leptin deficiency will permit to elucidate key aspects of human endocrine and immune function, and will give new insights on the role of leptin in human endocrine regulation.
Leptin administration in leptin-deficient children will possibly increase energy and fat metabolism by increasing sympathetic nervous system activity. To test this hypothesis, we will measure food intake, energy expenditure, body composition and sympathetic nervous system activity in patients homozygous due to a leptin gene mutation, before and throughout the leptin replacement therapy.
Leptin modulates T-cell function and affects the phagocytic activity of macrophages. Immune function will be assessed during the course of this study. Specifically, tests for antibody, complement and phagocytic function, tests for T-cell immunity, flow cytometry, TREC PCR, thymus imaging studies will be performed. Antibody levels for pathogen organisms will be checked and the child will be vaccinated if needed.
Leptin also has important roles on thyroid, adrenal and gonadal functions. Morevover, leptin is correlated with levels of lipids, glucose and insulin. To test the effects of leptin replacement in leptin-deficient humans, endocrine and metabolic parameters will be measured, before and during treatment.
Leptin determines changes on bone mineral density. To evaluate these changes, bone function and densitometry will also be assessed in this leptin deficient child.
Finally, leptin may have a role in brain growth and development. We will conduct volumetric brain imaging studies in this patient during the course of leptin replacement, ensuring safe exposure to radiation. Neuropsychological evaluation will also be undertaken.