Search

Lipodystrophies are a group of disorders characterized by absence or loss of adipose tissue and abnormal fat distribution, commonly accompanied by metabolic dysregulation. Although considered rare disorders, their prevalence in the general population is not well understood. We aimed to evaluate the clinical and genetic prevalence of lipodystrophy disorders in a large clinical care cohort. We interrogated the electronic health record (EHR) information of >1.3 million adults from the Geisinger Health System for lipodystrophy diagnostic codes. We estimate a clinical prevalence of disease of 1 in 20,000 individuals. We performed genetic analyses in individuals with available genomic data to identify variants associated with inherited lipodystrophies and examined their EHR for comorbidities associated with lipodystrophy. We identified 16 individuals carrying the p.R482Q pathogenic variant in LMNA associated with Dunnigan familial partial lipodystrophy. Four had a clinical diagnosis of lipodystrophy, whereas the remaining had no documented clinical diagnosis despite having accompanying metabolic abnormalities. We observed a lipodystrophy-associated variant carrier frequency of 1 in 3,082 individuals in our cohort with substantial burden of metabolic dysregulation. We estimate a genetic prevalence of disease of ∼1 in 7,000 in the general population. Partial lipodystrophy is an underdiagnosed condition. and its prevalence, as defined molecularly, is higher than previously reported. Genetically guided stratification of patients with common metabolic disorders, like diabetes and dyslipidemia, is an important step toward precision medicine., (© 2019 by the American Diabetes Association.)

Mutations in different domains of the LMNA (lamin A/C) gene encoding nuclear envelope proteins lamin A and lamin C cause familial partial lipodystrophy (Dunnigan variety), dilated cardiomyopathy, and autosomal dominant forms of Emery-Dreifuss and limb-girdle muscular dystrophies. The objective of this study was to evaluate LMNA variants in two families with familial partial lipodystrophy (Dunnigan variety) who also had cardiac conduction system defects and other manifestations related to cardiomyopathy. We performed mutational analysis of the lamin A/C gene in affected and unaffected subjects by deoxyribonucleic acid sequencing of the exons. Two novel missense mutations were identified in exon 1 of the lamin A/C gene. One mutation, R28W (CGG-->TGG), affected the amino-terminal head domain, and the other, R62G (CGC-->GGC), affected the alpha-helical rod domain. Affected subjects from both families had an increased prevalence of cardiac manifestations, such as atrioventricular conduction defects, atrial fibrillation, and heart failure due to ventricular dilatation, as well as pacemaker implantation. The proband from one of the families also had proximal muscle weakness. Novel genetic defects in the LMNA gene in two families with the Dunnigan variety of familial partial lipodystrophy, cardiac conduction system defects, and other manifestations related to cardiomyopathy suggest the occurrence of a multisystem dystrophy syndrome due to LMNA mutations.

Familial partial lipodystrophy, Dunnigan type (FPLD; Mendelian Inheritance in Man #151660), is an autosomal dominant disorder characterized by loss of s.c. fat from the extremities and trunk since puberty and predisposition to insulin resistance and its complications. However, for lack of recognition of affected men, previous studies could not ascertain any gender differences in phenotypic expression. Therefore, anthropometric variables and prevalence of diabetes mellitus, dyslipidemia, hypertension, and atherosclerotic vascular disease were compared among 17 postpubertal men and 22 women with FPLD from eight pedigrees. All individuals completed a questionnaire, and fasting blood was analyzed for glucose, insulin, and lipoprotein concentrations. Both affected men and women had similar patterns of fat loss. Compared with the affected men, women had higher prevalence of diabetes (18% and 50%, respectively; P = 0.05) and atherosclerotic vascular disease (12% and 45%, respectively; P = 0.04) and had higher serum triglycerides (median values, 2.27 and 4.25 mmol/L, respectively; P = 0.02) and lower high-density lipoprotein cholesterol concentrations (age-adjusted means, 0.94 and 0.70 mmol/L, respectively; P = 0.04). The prevalence of hypertension and fasting serum insulin concentrations were similar. In conclusion, women with FPLD are more severely affected with metabolic complications of insulin resistance than men. These observations raise the possibility that women with generalized and regional obesity may also have more severe metabolic sequelae of insulin resistance.