ABCA1 and metabolic syndrome: This positive relationship between ABCA1 function and blood HDL-C concentrations has previously only been described in humans with known ABCA1 mutations.[34] and was not observed in fibroblasts taken from patients with the metabolic syndrome.[35] It had been thought that increased intravascular HDL remodelling and catabolism were the cause of lower HDL-C concentrations in patients with type 2 diabetes [36] but our observations suggest that reduced HDL synthesis as a result of impaired ABCA1 function may be a factor.