How to diagnose a lipodystrophy syndrome.

The spectrum of adipose tissue diseases ranges from obesity to lipodystrophy, and is accompanied by insulin resistance syndrome, which promotes the occurrence of type 2 diabetes, dyslipidemia and cardiovascular complications. Lipodystrophy refers to a group of rare diseases characterized by the generalized or partial absence of adipose tissue, and occurs with or without hypertrophy of adipose tissue in other sites. They are classified as being familial or acquired, and generalized or partial. The genetically determined partial forms usually occur as Dunnigan syndrome, which is a type of laminopathy that can also manifest as muscle, cardiac, neuropathic or progeroid involvement. Gene mutations encoding for PPAR-gamma, Akt2, CIDEC, perilipin and the ZMPSTE 24 enzyme are much more rare. The genetically determined generalized forms are also very rare and are linked to mutations of seipin AGPAT2, FBN1, which is accompanied by Marfan syndrome, or of BANF1, which is characterized by a progeroid syndrome without insulin resistance and with early bone complications. Glycosylation disorders are sometimes involved. Some genetically determined forms have recently been found to be due to autoinflammatory syndromes linked to a proteasome anomaly (PSMB8). They result in a lipodystrophy syndrome that occurs secondarily with fever, dermatosis and panniculitis. Then there are forms that are considered to be acquired. They may be iatrogenic (protease inhibitors in HIV patients, glucocorticosteroids, insulin, graft-versus-host disease, etc.), related to an immune system disease (sequelae of dermatopolymyositis, autoimmune polyendocrine syndromes, particularly associated with type 1 diabetes, Barraquer-Simons and Lawrence syndromes), which are promoted by anomalies of the complement system. Finally, lipomatosis is currently classified as a painful form (adiposis dolorosa or Dercum's disease) or benign symmetric multiple form, also known as Launois-Bensaude syndrome or Madelung's disease, which are sometimes related to mitochondrial DNA mutations, but are usually promoted by alcohol. In addition to the medical management of metabolic syndrome and the sometimes surgical treatment of lipodystrophy, recombinant leptin provides hope for genetically determined lipodystrophy syndromes, whereas modifications in antiretroviral treatment and tesamorelin, a GHRH analog, is effective in the metabolic syndrome of HIV patients. Other therapeutic options will undoubtedly be developed, dependent on pathophysiological advances, which today tend to classify genetically determined lipodystrophy as being related to laminopathy or to lipid droplet disorders.

Phenotype and HFE genotype in a population with abnormal iron markers recruited from an Endocrinology Department.

OBJECTIVE: The aim of this study was to describe HFE genotype in a population of patients with altered iron markers recruited in an Endocrinology Department and to define the possible phenotype-genotype relationships. METHODS: A total of 156 patients with high serum ferritin concentrations (>300 ng/ml) or transferrin saturation (>45%) (I group), and a control group of 106 healthy subjects (C group) underwent HFE genotyping (classical C282Y and H63D mutations). We also examined the main genetic features of subgroups in I according to the presence (D) or the absence (ND) of diabetes. RESULTS: (1) The genotypes were significantly different in the I and C groups (P<0.001), with an increased frequency of major 282Y allele in the I group (35% vs 7.5%), but not of minor 63D allele (17 vs 18.5%). (2) The genotype of D and ND groups also differed (P<0.0001), with a lower frequency of C282 heterozygosity (P<0.0001) in the D group, and a higher prevalence of H63D heterozygosity in the D vs ND groups (P<0.01). (3) The phenotypic comparison of D and ND groups also showed a higher mean body mass index, age, and serum ferritin concentration, as well as an increased proportion of males with increased liver enzymes in the D group. CONCLUSION: This population harboring abnormal iron markers had a different HFE genotype and a higher 282Y allele frequency than the control population. This suggests that blood iron markers could be checked in etiological investigations of metabolic disturbances to identify patients who should undergo genotyping, since approximately 20% were diagnosed with C282Y homozygosity.