Endocrine Abstracts

Background: Congenital lipodystrophy is an uncommon genetic disorder, with an incidence of less than one in a million globally. It involves a lack of subcutaneous adipose tissue, leading to the abnormal accumulation of fat within internal organs, especially the liver, which can result in complications like cirrhosis, hypertriglyceridemia, and insulin resistance, eventually causing diabetes. Here, we discuss a case of familial partial lipodystrophy (FPL), initially mistaken for Type 1 Diabetes Mellitus (T1DM).

Case Report: A 32-year-old Caucasian female was first referred to the lipid clinic for eruptive xanthomas and a triglyceride level of 67. Her HbA1c was elevated at 94 mmol/mol. She had no major medical history other than excessive alcohol intake (40-50 units/week) and a parent with T2DM. Despite a BMI of 20.7, she was placed on a T1DM regimen with basal-bolus insulin, though she required unusually high doses (over 150 units/day) given her weight of 61 kg. Physical examination showed fat loss in her limbs and prominent shoulder musculature. Additional tests, including elevated C-peptide levels and negative diabetes auto-antibodies, suggested an alternate diagnosis. Genetic testing confirmed FPL, and the patient was referred to the National Severe Insulin Resistance Service, where she began metreleptin therapy. After starting metreleptin, both her blood glucose and insulin requirements decreased.

Conclusion: This case underscores the importance of not defaulting to a T1DM diagnosis when clinical features are atypical, especially with negative auto-antibodies. The patient’s complex diabetes resulted from insulin resistance due to FPl. Metreleptin, a human leptin analog, proved effective in improving glycemic control in this context.