Progressive Generalized Lipodystrophy as a Manifestation of Autoimmune Polyglandular Syndrome Type 1

We describe APS1 in a boy with generalized lipodystrophy, oral candidiasis, autoimmune hepatitis and adrenal insufficiency. It is the first time when generalized lipodystrophy is associated with APS1.

Body fat distribution and metabolic variables in patients with neonatal progeroid syndrome

Neonatal progeroid syndrome (NPS), also known as Wiedemann-Rautenstrauch Syndrome, is a rare autosomal recessive disorder characterized by accelerated aging and lipodystrophy from birth. Affected children have extreme intrauterine growth retardation, poor postnatal weight gain, and characteristic facial dysmorphic features such as a triangular shape, pinched nose, pseudohydrocephalus with wide fontanelles and prominent subcutaneous (sc) veins. Generalized loss of sc fat has been reported as a cardinal feature; however, the pattern of fat loss and its association with insulin resistance and its metabolic complications have not been systematically studied. The aim of the current study was to examine body fat distribution and body composition in two girls with NPS using anthropometric measures, whole-body magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DEXA), and to assess metabolic complications such as hyperinsulinemia and dyslipidemia. Both the girls (aged 17 years and 10 years, respectively) had generalized paucity of sc fat on physical examination. However, measurements of skin-fold thickness revealed that sc fat was decreased over the extremities, but preserved over the chest and abdomen. MRI studies confirmed the presence of normal amounts of sc truncal fat, and marked loss of fat from the face and distal extremities. Striking fat loss was also noted in the paravertebral and lateral gluteal regions. Interestingly, body composition analysis with DEXA scan revealed a marked reduction in both the fat and lean tissue mass. Fasting glucose, lipids and insulin levels were not elevated. We conclude that patients with NPS do not have generalized lipodystrophy as previously reported, but fat loss is confined to the face, distal extremities, and possibly the paravertebral and lateral gluteal regions. Metabolic abnormalities related to insulin resistance are also uncommon in this condition.

[Seipin/BSCL2-related motor neuron disease: Seipinopathy is a novel conformational disease associated with endoplasmic reticulum stress]

In 2004, heterozygous mutations (N88S, S90L) in the Seipin/BSCL2 gene were identified in two autosomal dominant motor neuron diseases, distal hereditary motor neuropathy type V (OMIM #182960) and Silver syndrome (OMIM #270685). The Seipin/BSCL2 gene was originally identified as a candidate gene for congenital generalized lipodystrophy type 2 (CGL2) (OMIM #269700). Individuals with homozygous null mutations in seipin have severe lipoatrophy, insulin resistance, hypertriglyceridemia, and mental retardation without any abnormality of the motor neurons. Recent phenotype analyses of the N88S and S90L mutations have revealed a wide spectrum of Seipin/BSCL2-related motor neuron diseases, including Silver syndrome, distal hereditary motor neuropathy type V, variants of Charcot-Marie-Tooth disease type 2, and spastic paraplegia 17; therefore, these diseases should be termed "seipinopathies". Seipin is a transmembrane protein that is localized in the endoplasmic reticulum (ER). Interestingly, the N88S and S90L mutations both disturb the N-glycosylation motif, suggesting that improper glycosylation of seipin is closely associated with the pathogenesis of motor neuron diseases. Our recent study demonstrated that seipin is proteolytically cleaved into N and C-terminal fragments and then polyubiquitinated. The N88S and S90L mutations enhance ubiquitination and degradation by UPS, and N88S and S90L mutants appear to be improperly folded, resulting in their accumulation in the ER. Furthermore, expression of mutant seipin in cultured cells activates UPR stress and induces ER stress-mediated apoptosis. Our findings suggest that seipin-related motor neuron diseases, seipinopathies are novel conformational diseases, and we propose that the pathological process of these diseases is tightly associated with ER stress-mediated cell death.