Hutchinson-Gilford Progeria Syndrome: Cellular Mechanisms and Therapeutic Perspectives.

In humans, aging is characterized by a gradual decline of physical and psychological functions, with the concomitant onset of chronic-degenerative diseases, which ultimately lead to death. The study of Hutchinson-Gilford progeria syndrome (HGPS), a premature aging disorder that recapitulates several features of natural aging, has provided important insights into deciphering the aging process. The genetic origin of HGPS is a de novo point mutation in the LMNA gene that drives the synthesis of progerin, mutant version of lamin A. Progerin is aberrantly anchored to the nuclear envelope disrupting a plethora of molecular processes; nonetheless, how progerin exerts a cascade of deleterious alterations at the cellular and systemic levels is not fully understood. Over the past decade, the use of different cellular and animal models for HGPS has allowed the identification of the molecular mechanisms underlying HGPS, paving the way towards the development of therapeutic treatments against the disease. In this review, we present an updated overview of the biology of HGPS, including its clinical features, description of key cellular processes affected by progerin (nuclear morphology and function, nucleolar activity, mitochondrial function, protein nucleocytoplasmic trafficking and telomere homeostasis), as well as discussion of the therapeutic strategies under development.

Leukocyte Nuclear Morphology Alterations in Dilated Cardiomyopathy Caused by a Lamin AC Truncating Mutation (LMNA/Ser431*) Are Modified by the Presence of a LAP2 Missense Polymorphism (TMPO/Arg690Cys).

The clinical phenotype of LMNA-associated dilated cardiomyopathy (DCM) varies even among individuals who share the same mutation. LMNA encodes lamin AC, which interacts with the lamin-associated protein 2 alpha (LAP2α) encoded by the TMPO gene. The LAP2α/Arg690Cys polymorphism is frequent in Latin America and was previously found to disrupt LAP2α-Lamin AC interactions in vitro. We identified a DCM patient heterozygous for both a lamin AC truncating mutation (Ser431*) and the LAP2α/Arg690Cys polymorphism. We performed protein modeling and docking experiments, and used confocal microscopy to compare leukocyte nuclear morphology among family members with different genotype combinations (wild type, LAP2α Arg690Cys heterozygous, lamin AC/Ser431* heterozygous, and LAP2α Arg690Cys/lamin AC Ser431* double heterozygous). Protein modeling predicted that 690Cys destabilizes the LAP2α homodimer and impairs lamin AC-LAP2α docking. Lamin AC-deficient nuclei (Ser431* heterozygous) showed characteristic blebs and invaginations, significantly decreased nuclear area, and increased elongation, while LAP2α/Arg690Cys heterozygous nuclei showed a lower perimeter and higher circularity than wild-type nuclei. LAP2α Arg690Cys apparently attenuated the effect of LMNA Ser431* on the nuclear area and fully compensated for its effect on nuclear circularity. Altogether, the data suggest that LAP2α/Arg690Cys may be one of the many factors contributing to phenotype variation of LMNA-associated DCM.

Síndrome de Progeria Hutchinson-Gilford

El Síndrome de Progeria de Hutchinson- Gilford es una enfermedad que se caracteriza por el envejecimiento prematuro en niños, debido a una mutación en el gen de Lámina tipo A involucrado en la mitosis celular. En el presente trabajo, con el objetivo de dar difusión al conocimiento de esta enfermedad, se señalan los procesos involucrados en su desarrollo, así como los avances científicos y el alcance de nuevas ventanas terapéuticas. La revisión se realizó consultando artículos en español e inglés empleando los motores de búsqueda Pubmed y Google Académico. La actualización del personal de salud sobre las enfermedades genéticas congénitas es de vital importancia para mejorar su detección, atención y manejo.

Hutchinson-Gilford Progeria Syndrome is a disease characterized by premature aging in children, due to a mutation in the Lamina type A, gene involved in cellular mitosis. In the present work, with the aim of spreading the knowledge of this disease, the processes involved in its development, the scientific advances, and the scope of new therapeutic treatments were summarized. The review was carried out by consulting articles in Spanish and English using the Pubmed and Google Academic search engines. The updating of health personnel on congenital genetic diseases is of vital importance to improve their detection, care and management.

A Síndrome de Hutchinson-Gilford Progeria é uma doença caracterizada pelo envelhecimento prematuro em crianças, devido a uma mutação no gene lamina tipo A envolvido na mitose celular. No presente trabalho, como objetivo de divulgar o conhecimento desta doença, são indicados os processos envolvidos no seu desenvolvimento, bem como os avanços científicos e o âmbito de novas janelas terapêuticas. A análise foi realizada através da consulta de artigos em espanhol e inglês utilizando os motores de busca pubmed e Google Scholar. A atualização do pessoal de saúde sobre doenças genéticas congénitas é de importância vital para melhorar a sua deteção, cuidados e gestão.

A case report of a novel mutation in lamin A/C gene related with risk of sudden death.

Background: Lamin A/C-associated heart disease is a group of clinical entities characterized by a mutation in the LMNA gene. Multiple cardiac phenotypes have been described, including a higher risk of sudden death. Case summary: A 23-year-old asymptomatic patient with an extensive history of heart disease in the family consulted the clinic. He had a genetic test performed when he was born revealing a new frameshift mutation in the LMNA gene. Numerous cardiac function tests were ordered, which initially were normal. After a year of follow-up, Holter monitoring was positive for episodes of nonsustained ventricular tachycardia (NSVT). Because of the risk factors and higher likelihood of sudden death, a decision was made to offer an implantable cardiac defibrillator (ICD), which was performed without complications. The patient continues the follow-up with cardiology and electrophysiology consisting of yearly cardiac imaging and device recordings. Discussion: Lamins are nuclear proteins involved in various cellular processes in myocardial cells. Therefore, mutations are associated with wide phenotypic alterations. The mutation described here was not previously reported in the literature. In the face of an undescribed mutation, the decision to use an ICD for primary prevention of sudden death is challenging. Because of the episodes of NSVT and a higher likelihood of risk of sudden death due to male sex and first-degree atrioventricular block, the decision to use an ICD was made for this patient, with no complications.

Colocalization Analysis of Peripheral Myelin Protein-22 and Lamin-B1 in the Schwann Cell Nuclei of Wt and TrJ Mice.

Myelination of the peripheral nervous system requires Schwann cells (SC) differentiation into the myelinating phenotype. The peripheral myelin protein-22 (PMP22) is an integral membrane glycoprotein, expressed in SC. It was initially described as a growth arrest-specific (gas3) gene product, up-regulated by serum starvation. PMP22 mutations were pathognomonic for human hereditary peripheral neuropathies, including the Charcot-Marie-Tooth disease (CMT). Trembler-J (TrJ) is a heterozygous mouse model carrying the same pmp22 point mutation as a CMT1E variant. Mutations in lamina genes have been related to a type of peripheral (CMT2B1) or central (autosomal dominant leukodystrophy) neuropathy. We explore the presence of PMP22 and Lamin B1 in Wt and TrJ SC nuclei of sciatic nerves and the colocalization of PMP22 concerning the silent heterochromatin (HC: DAPI-dark counterstaining), the transcriptionally active euchromatin (EC), and the nuclear lamina (H3K4m3 and Lamin B1 immunostaining, respectively). The results revealed that the number of TrJ SC nuclei in sciatic nerves was greater, and the SC volumes were smaller than those of Wt. The myelin protein PMP22 and Lamin B1 were detected in Wt and TrJ SC nuclei and predominantly in peripheral nuclear regions. The level of PMP22 was higher, and those of Lamin B1 lower in TrJ than in Wt mice. The level of PMP22 was higher, and those of Lamin B1 lower in TrJ than in Wt mice. PMP22 colocalized more with Lamin B1 and with the transcriptionally competent EC, than the silent HC with differences between Wt and TrJ genotypes. The results are discussed regarding the probable nuclear role of PMP22 and the relationship with TrJ neuropathy.

Isolated Left Ventricular Apical Hypoplasia without Lamin A/C Gene Mutation

Abstract Isolated left ventricular apical hypoplasia is a rare cardiomyopathy, with a broad range of clinical presentations. Since this entity was already described in association with osteomuscular diseases, mutation in the Lamin A/C gene has been regarded as a possible cause of this disease. This study describes the case of an asymptomatic teenager with isolated left ventricular apical hypoplasia and arthrogriposis but with no mutations in the entire Lamin A/C gene.

Loss of lamin-B1 and defective nuclear morphology are hallmarks of astrocyte senescence in vitro and in the aging human hippocampus.

The increase in senescent cells in tissues, including the brain, is a general feature of normal aging and age-related pathologies. Senescent cells exhibit a specific phenotype, which includes an altered nuclear morphology and transcriptomic changes. Astrocytes undergo senescence in vitro and in age-associated neurodegenerative diseases, but little is known about whether this process also occurs in physiological aging, as well as its functional implication. Here, we investigated astrocyte senescence in vitro, in old mouse brains, and in post-mortem human brain tissue of elderly. We identified a significant loss of lamin-B1, a major component of the nuclear lamina, as a hallmark of senescent astrocytes. We showed a severe reduction of lamin-B1 in the dentate gyrus of aged mice, including in hippocampal astrocytes, and in the granular cell layer of the hippocampus of post-mortem human tissue from non-demented elderly. The lamin-B1 reduction was associated with nuclear deformations, represented by an increased incidence of invaginated nuclei and loss of nuclear circularity in senescent astrocytes in vitro and in the aging human hippocampus. We also found differences in lamin-B1 levels and astrocyte nuclear morphology between the granular cell layer and polymorphic layer in the elderly human hippocampus, suggesting an intra-regional-dependent aging response of human astrocytes. Moreover, we described senescence-associated impaired neuritogenic and synaptogenic capacity of mouse astrocytes. Our findings show that reduction of lamin-B1 is a conserved feature of hippocampal cells aging, including astrocytes, and shed light on significant defects in nuclear lamina structure which may contribute to astrocyte dysfunctions during aging.

Loss of Dystroglycan Drives Cellular Senescence via Defective Mitosis-Mediated Genomic Instability.

Nuclear ß-dystroglycan (ß-DG) is involved in the maintenance of nuclear architecture and function. Nonetheless, its relevance in defined nuclear processes remains to be determined. In this study we generated a C2C12 cell-based DG-null model using CRISPR-Cas9 technology to provide insights into the role of ß-DG on nuclear processes. Since DG-null cells exhibited decreased levels of lamin B1, we aimed to elucidate the contribution of DG to senescence, owing to the central role of lamin B1 in this pathway. Remarkably, the lack of DG enables C2C12 cells to acquire senescent features, including cell-cycle arrest, increased senescence-associated-ß-galactosidase activity, heterochromatin loss, aberrant nuclear morphology and nucleolar disruption. We demonstrated that genomic instability is one driving cause of the senescent phenotype in DG-null cells via the activation of a DNA-damage response associated with mitotic failure, as shown by the presence of multipolar mitotic spindles, which in turn induced the formation of micronuclei and γH2AX foci (DNA-damage marker), telomere shortening and p53/p21 upregulation. Altogether, these events might ultimately lead to premature senescence, impeding the replication of the damaged genome. In summary, we present evidence supporting a role for DG in protecting against senescence, through the maintenance of proper lamin B1 expression/localization and proper mitotic spindle organization.

Enhanced nuclear protein export in premature aging and rescue of the progeria phenotype by modulation of CRM1 activity.

The study of Hutchinson-Gilford progeria syndrome (HGPS) has provided important clues to decipher mechanisms underlying aging. Progerin, a mutant lamin A, disrupts nuclear envelope structure/function, with further impairment of multiple processes that culminate in senescence. Here, we demonstrate that the nuclear protein export pathway is exacerbated in HGPS, due to progerin-driven overexpression of CRM1, thereby disturbing nucleocytoplasmic partitioning of CRM1-target proteins. Enhanced nuclear export is central in HGPS, since pharmacological inhibition of CRM1 alleviates all aging hallmarks analyzed, including senescent cellular morphology, lamin B1 downregulation, loss of heterochromatin, nuclear morphology defects, and expanded nucleoli. Exogenous overexpression of CRM1 on the other hand recapitulates the HGPS cellular phenotype in normal fibroblasts. CRM1 levels/activity increases with age in fibroblasts from healthy donors, indicating that altered nuclear export is a common hallmark of pathological and physiological aging. Collectively, our findings provide novel insights into HGPS pathophysiology, identifying CRM1 as potential therapeutic target in HGPS.

Metabolomic profiling suggests systemic signatures of premature aging induced by Hutchinson-Gilford progeria syndrome.

INTRODUCTION: Hutchinson-Gilford Progeria Syndrome (HGPS) is an extremely rare genetic disorder. HGPS children present a high incidence of cardiovascular complications along with altered metabolic processes and an accelerated aging process. No metabolic biomarker is known and the mechanisms underlying premature aging are not fully understood. OBJECTIVES: The present work aims to evaluate the metabolic alterations in HGPS using high resolution mass spectrometry. METHODS: The present study analyzed plasma from six HGPS patients of both sexes (7.7 ± 1.4 years old; mean ± SD) and eight controls (8.6 ± 2.3 years old) by LC-MS/MS in high-resolution non-targeted metabolomics (Q-Exactive Plus). Targeted metabolomics was used to validate some of the metabolites identified by the non-targeted method in a triple quadrupole (TSQ-Quantiva). RESULTS: We found several endogenous metabolites with statistical differences between control and HGPS children. Multivariate statistical analysis showed a clear separation between groups. Potential novel metabolic biomarkers were identified using the multivariate area under ROC curve (AUROC) based analysis, showing an AUC value higher than 0.80 using only two metabolites, and tending to 1.00 when increasing the number of metabolites in the AUROC model. Taken together, changed metabolic pathways involve sphingolipids, amino acids, and oxidation of fatty acids, among others. CONCLUSION: Our data show significant alterations in cellular energy use and availability, in signal transduction, and lipid metabolites, adding new insights on metabolic alterations associated with premature aging and suggesting novel putative biomarkers.

Telomeric Repeat-Binding Factor Homologs in Entamoeba histolytica: New Clues for Telomeric Research.

Telomeric Repeat Binding Factors (TRFs) are architectural nuclear proteins with critical roles in telomere-length regulation, chromosome end protection and, fusion prevention, DNA damage detection, and senescence regulation. Entamoeba histolytica, the parasite responsible of human amoebiasis, harbors three homologs of human TRFs, based on sequence similarities to their Myb DNA binding domain. These proteins were dubbed EhTRF-like I, II and III. In this work, we revealed that EhTRF-like I and II share similarity with human TRF1, while EhTRF-like III shares similarity with human TRF2 by in silico approach. The analysis of ehtrf-like genes showed they are expressed differentially under basal culture conditions. We also studied the cellular localization of EhTRF-like I and III proteins using subcellular fractionation and western blot assays. EhTRF-like I and III proteins were enriched in the nuclear fraction, but they were also present in the cytoplasm. Indirect immunofluorescence showed that these proteins were located at the nuclear periphery co-localizing with Lamin B1 and trimethylated H4K20, which is a characteristic mark of heterochromatic regions and telomeres. We found by transmission electron microscopy that EhTRF-like III was located in regions of more condensed chromatin. Finally, EMSA assays showed that EhTRF-like III forms specific DNA-protein complexes with telomeric related sequences. Our data suggested that EhTRF-like proteins play a role in the maintenance of the chromosome ends in this parasite.

Role of α-Dystrobrevin in the differentiation process of HL-60 cells.

The α-Dystrobrevin gene encodes at least five different protein isoforms, expressed in diverse tissues. The α-Dystrobrevin-1 isoform (α-Db-1) is a member of the cytoplasmic dystrophin-associated protein complex, which has a C-terminal extension comprising at least three tyrosine residues susceptible to phosphorylation in vivo. We previously described α-Db in stem-progenitor cells and blood neutrophils as playing a scaffolding role and, in association with kinesin and microtubules, α-Db promotes platelet-granule trafficking. Additionally, the microtubules must establish a balanced interaction with the lamina A/C network for appropriate nuclear morphology. Considering that the most outstanding feature during neutrophil differentiation is nuclei lobulation, we hypothesized that α-Db might possess a pivotal function during the neutrophil differentiation process. Western Blot (WB) and confocal microscope assays evidenced a differential pattern expression and a subcellular redistribution of α-Db in neutrophils derived from HL-60 cells. At the end of the differentiation process, we detected an important diminution in the expression of tubulin, kinesin, and α-Db-1. Knockdown of α-Db prevented nuclei lobulation, increased Lamin A/C and syne1 expression and augmented the roughness of derived neutrophil membrane and disturbed filopodia assembly. Our results suggest that HL-60 cells undergo extensive cytoskeletal reorganization including α-Db in order to possess lobulated nuclei when they further differentiate into neutrophils.

Depleted lamin B1: a possible marker of the involvement of senescence in endometriosis?

PROPOSE: Endometriosis is a benign disease characterized by implantation and the growth of endometrial tissue outside the uterine cavity and it shares similarities with cancer. Lamin B1, p16 and p21 play a role on cell cycle regulation, development, cell repair and its activities are related to cancers. Considering the similarities between endometriosis and cancer, the aim of the present cross-sectional study is to detect p16, p21 and Lamin B1 in the ectopic endometrium of patients with endometriosis (n = 8) with eutopic (n = 8) and control endometrium (n = 8) and relate them to the maintenance and development of endometriosis. METHODS: Biopsies were obtained from both eutopic and ectopic, from deep infiltrating lesions, endometrium frozen and used for immunofluorescent (p16) or immunohistochemistry procedures (p16, p21, lamin B1). RESULTS: Detected higher lamin B1 in the eutopic endometrium when compared with ectopic endometrium, with no differences between endometriosis tissue with control endometrium. Similar presence of p16 in all groups of patients and no p21 detection was observed. CONCLUSION: We observed reduced detection of lamin B1 in the ectopic endometrium raising the possibility that the presence of senescent cells might be contributing to the maintenance and progression of endometriosis by apoptosis resistance and peritoneal stress inherent of the disease.

Autosomal dominant leukodystrophy presenting as Alzheimer's-type dementia.

Autosomal dominant leukodystrophy is a neurodegenerative disorder caused by either point mutations or duplication of the lamin B1 gene on chromosome 5q23. The typical clinical picture consists of autonomic symptoms as well as cerebellar and pyramidal signs. Here we present the case of a 57-year-old female referred to our clinic due to cognitive decline. Neurological examination was significant for cognitive impairment as well as pyramidal and cerebellar signs. Brain MRI displayed diffuse hyperintense lesions in the subcortical white matter, pontine nuclei, brachium pontis and restiform body. The diagnosis was confirmed via genetic testing. Autosomal dominant leukodystrophy should be included in the differential diagnosis of patients presenting with cognitive impairment, motor signs, and leukodystrophy-like images.

Avaliação bioquímica, hormonal e genética das famílias de duas pacientes brasileiras portadoras de lipodistrofia parcial familiar tipo 2 / Biochemical, hormonal and genetic evaluation of the families of two Brazilian patients with type 2 familial partial lipodystrophy

OBJETIVO: Avaliar características clínicas, bioquímicas, hormonais e genéticas de familiares de duas pacientes portadoras de lipodistrofia parcial familiar (FPLD) tipo 2. MATERIAIS E MÉTODOS: Foram avaliados 50 indivíduos de duas famílias brasileiras não relacionadas a partir de dois propósitos com fenótipo de FPLD. Foi confirmada a mutação no éxon 8 do gene LMNA em 18 destes e identificada a substituição em heterozigose no códon 482, resultando na mutação p.R482W. Com base na presença ou não da mutação, os indivíduos foram separados em afetados e não afetados, e comparados quanto a parâmetros clínicos, bioquímicos e hormonais. RESULTADOS: Indivíduos afetados tiveram 2,8 vezes mais chance de manifestar diabetes e síndrome dos ovários policísticos (SOP), maiores índices HOMA-IR, níveis de insulina e de triglicérides e menores níveis de leptina. Essas alterações precedem o início do diabetes, pois foram evidenciadas nos afetados diabéticos e não diabéticos. Foi constatada heterogeneidade fenotípica entre os portadores da mutação. CONCLUSÃO: A mutação no gene da LMNA é determinante de alterações clínicas, bioquímicas e hormonais que implicam deterioração metabólica nos portadores da mutação.

OBJECTIVE: To evaluate clinical, biochemical, hormonal and genetic characteristics of relatives of two patients with familial partial lipodystrophy (FPLD) type 2. MATERIALS AND METHODS: Fifty subjects, members of two non-related Brazilian families from two different probands with FPLD phenotype, were evaluated. A mutation in exon 8 of LMNA gene was confirmed in 18 of them, and a heterozygous substitution at codon 482 was identified, predicting a p.R482W mutation. Based on the presence or absence of the mutation, subjects were classified in affected and unaffected, and compared in terms of clinical, biochemical and hormonal parameters. RESULTS: Affected subjects were 2.8 times more likely to manifest diabetes and PCOS, higher HOMA-IR, insulin and triglyceride levels, and lower levels of leptin. These changes preceded the onset of diabetes, because they were observed in diabetic and non-diabetic affected patients. A phenotypic heterogeneity was found among mutation carriers. CONCLUSION: A mutation in the LMNA gene is a determinant of clinical, biochemical and hormonal changes that imply in metabolic deterioration in mutation carriers.

Changes in splicing factor expression are associated with advancing age in man.

Human ageing is associated with decreased cellular plasticity and adaptability. Changes in alternative splicing with advancing age have been reported in man, which may arise from age-related alterations in splicing factor expression. We determined whether the mRNA expression of key splicing factors differed with age, by microarray analysis in blood from two human populations and by qRT-PCR in senescent primary fibroblasts and endothelial cells. Potential regulators of splicing factor expression were investigated by siRNA analysis. Approximately one third of splicing factors demonstrated age-related transcript expression changes in two human populations. Ataxia Telangiectasia Mutated (ATM) transcript expression correlated with splicing factor expression in human microarray data. Senescent primary fibroblasts and endothelial cells also demonstrated alterations in splicing factor expression, and changes in alternative splicing. Targeted knockdown of the ATM gene in primary fibroblasts resulted in up-regulation of some age-responsive splicing factor transcripts. We conclude that isoform ratios and splicing factor expression alters with age in vivo and in vitro, and that ATM may have an inhibitory role on the expression of some splicing factors. These findings suggest for the first time that ATM, a core element in the DNA damage response, is a key regulator of the splicing machinery in man.

Liposuction in body-shaping treatment for Kobberling-Dunnigan syndrome / Lipoaspiração no tratamento do contorno corporal na síndrome de Kobberling-Dunnigan

INTRODUCTION: Kobberling-Dunnigan syndrome is characterized by a series of alterations in metabolism and body fat distribution. Body dysmorphism and the Cushingoid appearance may have negative social and psychological impacts on the patient, including difficulty with social adaptation. In such cases, liposuction is used with the aim of improving body contour, with consequent improvements in self-esteem. The results are long lasting when body weight is maintained. CASE REPORT: Liposuction of the back, abdomen, and cervical regions in a woman with Kobberling-Dunnigan syndrome led to significant improvement in her body shape, and the results were maintained nine months postoperatively.

INTRODUÇÃO: A síndrome de Kobberling-Dunnigan caracteriza-se por um conjunto de alterações metabólicas e de distribuição da gordura corporal. O dismorfismo corporal e o aspecto cushingoide trazem repercussões psicológicas e sociais, com dificuldade de ajuste social. Nesses casos, a lipoaspiração é empregada com o objetivo de melhorar o contorno corporal e, consecutivamente, as alterações de autoestima. Os resultados apresentam-se duradouros quando há manutenção do peso. RELATO DO CASO: Paciente do sexo feminino, portadora de síndrome de Kobberling-Dunnigan, submetida a lipoaspiração de dorso, abdome e região cervical, com melhora significativa do contorno corporal e manutenção dos resultados nove meses após a operação.

Atypical generalized lipoatrophy and severe insulin resistance due to a heterozygous LMNA p. T10I mutation / Lipoatrofia generalizada atípica e resistência insulínica grave devido à mutação p. T10I em heterozigose no gene LMNA

Lipodystrophies are a group of heterogeneous disorders characterized by the loss of adipose tissue and metabolic complications. The main familial forms of lipodystrophy are Congenital Generalized Lipodystrophy and Familial Partial Lipodystrophy (FPLD). FPLD may result from mutations in the LMNA gene. Besides FPLD, mutations in LMNA have been shown to be responsible for other inherited diseases called laminopathies. Here we describe the case of a 15-year-old girl who was referred to our service due to diabetes mellitus and severe hypertriglyceridemia. Physical examination revealed generalized loss of subcutaneous fat, confirmed by DEXA (total body fat 8.6 percent). As the patient presented with pubertal-onset of generalized lipodystrophy and insulin resistance, molecular analysis of the LMNA gene was performed. We identified a heterozygous substitution in exon 1 (c.29C>T) predicting a p.T10I mutation. In summary, we describe an atypical phenotype of lipodistrophy associated with a de novo appearance of the p.T10I mutation in LMNA gene.

As lipodistrofias são um grupo heterogêneo de doenças caracterizadas por perda de tecido adiposo e complicações metabólicas. As formas hereditárias mais importantes de lipodistrofias são: lipodistrofia congênita generalizada e lipodistrofia parcial familiar (LDPF). LDPF resulta de mutações no gene LMNA que codificam as lâminas tipo A. Além da LDPF, mutações no gene LMNA são responsáveis por outras doenças hereditárias, denominadas laminopatias. Descrevemos o caso de uma paciente de 15 anos de idade encaminhada por diabetes melito e hipertrigliceridemia grave. Ao exame físico, apresentava perda generalizada de gordura subcutânea que foi confirmada por DEXA (gordura corporal total 8,6 por cento). Como a paciente apresentava perda de gordura de início na puberdade e resistência insulínica, foi realizada análise molecular do gene LMNA. Identificamos uma substituição em heterozigose no éxon 1 (c.29C>T), resultando na mutação p.T10I. Em sumário, um caso de fenótipo atípico de lipodistrofia generalizada devido à mutação de novo p.T10I no gene LMNA é descrito.