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.

Analysis of a child with congenital muscular dystrophy due to a novel variant of the LMNA gene / 中华医学遗传学杂志

OBJECTIVE@#To report on a patient with congenital muscular dystrophy (CMD) due to a missense variant of LMNA gene and explore its pathogenicity.@*METHODS@#The 1-year-and-1-month-old boy has presented with motor development delay and elevation of muscle enzymes for more than half a year. Congenital myopathy was suspected. Following muscle biopsy, HE staining, immunostaining and electron microscopy were conducted to clarify the clinical diagnosis. Meanwhile, DNA was extracted from the child and his parents' peripheral venous blood samples. Trio-whole exome sequencing (trio-WES) was carried out to detect pathogenic variant in the child. Candidate variant was verified by Sanger sequencing and bioinformatic analysis.@*RESULTS@#Both light and electron microscopy showed a large area of necrotic muscle tissues with infiltration of inflammatory cells. Immunohistochemistry revealed a large amount of muscle cells to be diffusely positive for Dysferlin. The patient's motor delays, elevations of muscle enzymes and histopathological results suggested a clinical diagnosis of CMD. A de novo missense c.1072G>A (p.E358K) variant was detected in the LMNA gene by trio-WES. The variant was unreported previously (PS2) and was absent from major allele frequency databases (PM2). It was a loss of function variant and was considered as hotspot variant in the LMNA gene (PM1) as the amino acid (E), located in position 358, was highly conserved, and change of this amino acid was found to cause destruction of the filament domain (AA: 30-386), which may result in serious damage to the intermediate filament protein. Furthermore, c.1072G>A (p. E358K) in LMNA gene was also predicted to be pathogenic based on MutationTaster, PROVEAN and PolyPhen-2 (PP3) analysis. According to the guidelines of the American College of Medical Genetics and Genomics (ACMG), the variant was classified to be likely pathogenic (PS2+PM1+PM2+PP3).@*CONCLUSION@#The child's condition may be attributed to the de novo missense c.1072 G>A (p.E358K) variant of the LMNA gene. Above discovery has expanded the variant spectrum of the LMNA gene.

Inflammatory myopathy in the context of an unusual overlapping laminopathy

Summary Laminopathies are genetic disorders associated with alterations in nuclear envelope proteins, known as lamins. The LMNA gene encodes lamins A and C, and LMNA mutations have been linked to diseases involving fat (type 2 familial partial lipodystrophy [FPLD2]), muscle (type 2 Emery-Dreifuss muscular dystrophy [EDMD2], type 1B limb-girdle muscular dystrophy [LGMD1B], and dilated cardiomyopathy), nerves (type 2B1 Charcot-Marie-Tooth disease), and premature aging syndromes. Moreover, overlapping syndromes have been reported. This study aimed to determine the genetic basis of an overlapping syndrome in a patient with heart disease, myopathy, and features of lipodystrophy, combined with severe metabolic syndrome. We evaluated a 54-year-old woman with rheumatoid arthritis, chronic hypercortisolism (endogenous and exogenous), and a history of cured adrenal Cushing syndrome. The patient presented with a complex disorder, including metabolic syndrome associated with mild partial lipodystrophy (Köbberling-like); mild hypertrophic cardiomyopathy, with Wolff-Parkinson- White syndrome and atrial fibrillation; and limb-girdle inflammatory myopathy. Mutational analysis of the LMNA gene showed a heterozygous c.1634G>A (p.R545H) variant in exon 10 of LMNA. This variant has previously been independently associated with FPLD2, EDMD2, LGMD1B, and heart disease. We describe a new, LMNA-associated, complex overlapping syndrome in which fat, muscle, and cardiac disturbances are related to a p.R545H variant.

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.

Hutchinson-Gilford Progeria Syndrome with G608G LMNA Mutation

Hutchinson-Gilford progeria syndrome (HGPS) is a rare condition originally described by Hutchinson in 1886. Death result from cardiac complications in the majority of cases and usually occurs at average age of thirteen years. A 4-yr old boy had typical clinical findings such as short stature, craniofacial disproportion, alopecia, prominent scalp veins and sclerodermatous skin. This abnormal appearance began at age of 1 yr. On serological and hormonal evaluation, all values are within normal range. He was neurologically intact with motor and mental development. An echocardiogram showed calcification of aortic and mitral valves. Hypertrophy of internal layer at internal carotid artery suggesting atherosclerosis was found by carotid doppler sonography. He is on low dose aspirin to prevent thromboembolic episodes and on regular follow up. Gene study showed typical G608G (GGC- > GGT) point mutation at exon 11 in LMNA gene. This is a rare case of Hutchinson-Gilford progeria syndrome confirmed by genetic analysis in Korea.

Novel LMNA Gene Mutation in a Patient With Atypical Werner's Syndrome

Hutchinson-Gilford progeria syndrome (HGPS) and Werner's syndrome are representative types of progeroid syndrome. LMNA (Lamin A/C) gene mutation with atypical Werner's syndrome have recently been reported. Atypical Werner's syndrome with the severe metabolic complications, the extent of the lipodystrophy is associated with A133L mutation in the LMNA gene and these patients present with phenotypically heterogeneous disorders. We experienced a 15-yr-old Korean female with progeroid features, generalized lipodystrophy, hypertriglyceridemia, fatty liver, steatohepatitis, and type 2 diabetes mellitus. Skin fibroblasts from the patient showed marked abnormal nuclear morphology, compared with that from normal persons. Gene analysis revealed that this patient had T506del of exon 2 in the LMNA gene. We report here the first case of atypical Werner's syndrome with frameshift mutation that was caused by T506del.

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.