Background Lipodystrophies are rare disorders characterized by loss of adipose tissue, leading to severe metabolic and multisystem complications. Data on real-world management remain limited, particularly in Portugal. Objectives The objective of this study is to describe the clinical, metabolic, genetic, and therapeutic characteristics of patients with confirmed or suspected lipodystrophy followed at a Portuguese Endocrinology Outpatient Clinic. Methods We conducted a retrospective observational study including 21 patients with clinical suspicion or diagnosis of lipodystrophy. Demographic, clinical, laboratory, imaging, and genetic data were collected. Results The cohort was predominantly female (90.5%) with a median age at diagnosis of 49 years. Sixteen patients (76.2%) had familial partial lipodystrophy (FPLD), two (9.5%) had congenital generalized lipodystrophy, two (9.5%) had acquired generalized lipodystrophy, and one presented a complex syndromic form. Diabetes mellitus was present in 71.4% of patients and hypertriglyceridemia in 52.4%. Metabolic liver disease occurred in both generalized and partial forms. Autoimmune disorders affected 31.6% of patients, and cardiac involvement was observed in 23.8%. Genetic testing identified pathogenic or likely pathogenic variants in BSCL2 and PPARG in three patients, while most FPLD cases remained genetically unexplained. Metreleptin therapy in three patients with generalized lipodystrophy improved glycemic control, triglycerides, liver enzymes, and proteinuria. Dual-energy X-ray absorptiometry imaging supported the phenotypic characterization of adipose tissue loss. Conclusions Detailed physical examination, genetic testing, imaging, and early therapeutic interventions are critical for management. These findings align with European registry data and highlight the need for increased awareness and systematic evaluation in real-world clinical practice.

Acquired generalized lipodystrophy (AGL) is a rare metabolic disorder frequently associated with autoimmunity. Its etiology is incompletely understood, and the effect of adipose tissue loss on intestinal inflammation in AGL remains unclear. Using mass cytometry and single-cell RNA-seq, we observed an oligoclonal expansion of T cells in the periphery and inflamed intestine in a patient with AGL and Crohn's disease (AGLCD). To explore if loss of adipose tissue triggers lymphoproliferation, we studied lipodystrophic mice as a model for AGL. Unexpectedly, lipodystrophic mice did not show T cell expansion, were protected from colitis, and displayed a defect in the development of proinflammatory T cells, which could be reversed by allogeneic fat transplantations, indicating that clonal T cell expansion in AGLCD is not primarily caused by lipodystrophy. Instead, gene sequencing revealed a T cell-intrinsic de novo neuroblastoma RAS viral oncogene homolog (NRAS) mutation, implicating somatic mosaicism as a facilitator of clonal T cell expansion and intestinal inflammation in AGLCD.

Immune checkpoint inhibitors (ICI) have transformed cancer therapy but can induce a spectrum of endocrine complications. Acquired generalized lipodystrophy (AGL) is a rare adverse effect, leading to severe metabolic derangements including insulin-resistant diabetes, dyslipidemia, and hepatic steatosis. Marked hypoleptinemia is noted in these patients, and leptin-replacement therapy is known to be beneficial in patients with other forms of AGL. Though rare, T-cell lymphoma has been reported in patients with AGL on leptin therapy, and there has been much debate on the association between hyperleptinemia and cancer. The safety and efficacy of leptin therapy in patients with ICI-induced AGL and cancer are therefore not clear. We report a 66-year-old woman with metastatic lung adenocarcinoma who developed multiple endocrine disorders including AGL with metabolic abnormalities following pembrolizumab therapy. Initiation of daily metreleptin led to marked improvement in dyslipidemia, glycemic control, and hepatic steatosis, with no evidence of cancer recurrence after 2 years of leptin-replacement therapy. While further studies are warranted to establish the long-term efficacy and safety of leptin in ICI-induced AGL patients with a history of malignancy, this case report provides useful information for the management of these rare, challenging patients.

Insulin resistance is a condition wherein cells fail to adequately respond to insulin. It is a prevalent medical condition associated with several diseases, such as type 2 diabetes mellitus, metabolic syndrome, hypertension, obesity, and polycystic ovary syndrome. Insulin resistance may be involved in metabolic disturbances, such as hyperglycemia, hyperinsulinemia, dyslipidemia, hyperuricemia, endothelial dysfunction, elevated inflammatory markers, and a prothrombotic state. Severe insulin resistance syndromes are a heterogeneous group of rare disorders. These disorders are characterized by profound insulin resistance, substantial metabolic abnormalities, and different clinical manifestations and complications. They may be hereditary or acquired, caused by defects in insulin action and cellular responsiveness to insulin. Severe insulin resistance syndromes may also be due to aberrations in adipose tissue function and development. The majority of these disorders are associated with an increased risk of severe complications and mortality. This review aims to summarize the current knowledge on the epidemiology, pathophysiology, complications and prognosis of severe insulin resistance syndromes, as well as to categorize these syndromes by disease process, including defects in insulin receptor, intracellular insulin signaling defects, lipodystrophies, etc.

Lipodystrophy syndromes comprise a group of rare endocrine disorders characterized by the generalized or partial loss of adipose tissue. Affected individuals frequently display absolute or relative reductions in leptin, a key adipokine regulator of hunger-satiety signaling, and are predisposed to a range of metabolic and end-organ complications, often from a young age. The presentation and severity of lipodystrophy syndromes is largely dependent on the extent of adipose tissue loss while comorbidities often deteriorate with age. In this regard, optimizing care for children and adolescents with lipodystrophy syndromes is a pivotal step in supporting them into adulthood. To assist clinicians with limited experience of managing young patients with lipodystrophy syndromes, we describe our clinical approach to a series of pediatric patients with these rare diseases. The clinical history, diagnosis, disease management and follow-up care of 10 international pediatric patients with lipodystrophy syndromes are presented. Teaching points from each case study are also provided. Most of these cases are based on patients from our clinics with certain details changed to protect privacy. Others represent hypothetical scenarios based on our clinical experience supported by review of the medical literature and are included here for educational purposes. Our patients illustrate the broad phenotypic spectrum of lipodystrophy syndromes that can manifest early in life. We highlight the importance of timely and accurate diagnosis in guiding early disease management strategies to help reduce the risk of comorbidities. The challenges faced by clinicians managing pediatric patients with lipodystrophy syndromes and how these challenges may differ from adult patients are also explored. The cases presented in this manuscript may assist clinical teams to promptly diagnose and holistically manage young patients with lipodystrophy syndromes and help optimize clinical outcomes as they transition to adult care.