Despite advances in HIV care associated with HAART, many patients on HAART regimens develop physical and metabolic problems, including changes in body fat distribution (lipodystrophy), osteopenia and osteoporosis, dyslipidemia, and hyperlactatemia. Early studies suggest that protease inhibitors (PIs) were directly responsible for HIV Lipodystrophy Syndrome (HLS) and skeletal complications in HAART-treated patients. This study will compare HIV infected, HAART-treated children and youth and their uninfected counterparts to make connections between HAART, HLS, and skeletal and metabolic problems. The study is the first to address the prevalence and risk assessment of these complications in children, and will be useful in predicting long-term prognosis in HIV patients who use or have used HAART.

There will be three groups in the study. Group 1 participants will be uninfected volunteers who will receive no protocol-specific treatment or other intervention. Vertically infected HIV patients in Groups 2 and 3 will continue their current HAART either on a non-PI-containing regimen (Group 2) or a PI-containing regimen (Group 3). Screening evaluations will be conducted within 30 days prior to study entry. Study evaluations may be completed at study entry or over the course of up to 3 study visits. All participants will undergo whole body and regional DEXA scans (to assess bone density), measurements to determine sexual maturity, and blood work.