**3.1 Type 1 FPLD (FPLD1)**

Type 1 FPLD (OMIM #608600), also known as Köbberling-type lipodystrophy, was first reported by Köbberling et al. in 1971 [97]. The syndrome manifests loss of subcutaneous fat in the extremities and gluteus, with normal or increased fat deposition in the face, neck, and trunk [97]. The ratio of skin thickness from the abdomen to the thigh is significantly higher in these subjects, which can be used as a diagnostic method [98]. Diabetes and other metabolic complications including hypertension, insulin resistance, and severe hypertriglyceridemia develop during adulthood, with higher severity in women than men [98, 99]. Similar to other types of lipodystrophy, FPLD1 is an extremely rare genetic condition whose chance of occurrence is 1 in 15 million [6, 36]. Unfortunately, the causative loci for FPLD1 have not been identified to unravel the underlying genetic mechanism of the syndrome.
