There is no defined cut-off for having, or not having, polygenic lipodystrophy as it is not based on a single genetic variant. People will have between 0 and 22 polygenic lipodystrophy alleles and the investigators are looking for those with a combination of at least 11 genetic variants. They have identified approx 300 people in the EXTEND cohort who fit this criteria and will then recruit matched controls from those in the EXTEND cohort who have been identified as having the fewest number of risk alleles.