Analysis on six cases of Hutchinson-Gilford progeria syndrome / 中华内分泌代谢杂志

Objective@#To summarize the clinical characteristics of 6 children with Hutchinson-Gilford progeria syndrome, and to analyze the pathogenic genes carried by some patients.@*Methods@#The clinical data of 6 patients were summarized. The pathogenic genes of 4 families were analyzed. Genomic DNA was extracted from 3ml of the subject′s blood with EDTA anticoagulation. The first-generation sequencing technology was used to analyze the sequence of Lamin A/C(LMNA) gene and to identify the pathogenic mutation sites by comparing with normal sequencing results.@*Results@#All the children had typical clinical manifestations of the disease which has been previously reported in the literature, such as severe growth retardation, special skin manifestations, and distinctive craniofacial manifestations.Gene sequencing results revealed that 2 patients carried classical heterozygous mutation of LMNA c. 1824C>T(p.G608G). The other two patients carried atypical mutations of LMNA IVS8-4 C>A and c. 1968+ 2T>C, among which the mutation of IVS8-4 C>A has not been reported.@*Conclusions@#In Chinese children, both classical and non-classical mutations in LMNA gene lead to the occurrence of premature aging. It is easy to make a diagnosis based on clinical manifestations. Finding of the pathogenic gene may further confirm the diagnosis.

Partial lipodystrophy type 2 : One case report and literature review / 中华内分泌代谢杂志

Familial partial lipodystrophy type 2 (FPLD2) is an autosomal dominant disorder caused by mutations in LMNA gene,which is characterized by adolescent onset selective subcutaneous fat loss with metabolic abnormalities such as insulin resistance.Severe insulin resistance can cause acanthosis nigricans,pseudoacromegaly,ovarian dysfunction,glucose,and lipid metabolism disorders.Therefore,it is often misdiagnosed as metabolic syndrome,type 2 diabetes,polycystic ovary syndrome,acromegaly,and Cushing's syndrome.Through the analysis of the diagnosis and treatment of a case of FPLD2 with acromegaly,and the importance of tracing the origin of the disease is emphasized and also does the role of genetic testing in diagnosis.It suggests that clinicians should pay attention to the fat distribution of those similar patients,and make diagnosis and treatment timely.

Bioinformatic analysis of the sequences of lamins from different species / 中国实验动物学报

Objective Type A lamins are encoded by LMNA and a major component of the nuclear lamina, which have been suggested to play important roles in chromatin organization, transcription, DNA replication, and cell apoptosis. The aim of this study was to analyze the bioinformation of zebrafish lamins. Methods A phylogeny analysis was figured out with protein sequences of different species by Clustal X and MEGA 4?0 software. Then we compared the lamin protein sequences of different species with that of zebrafish by BLAST tool from NCBI. A figure of synteny analysis results was done with lamin sequence information of humans, murine and zebrafish cited from UCSC, Vega and Ensemble. Results The a?nalysis results showed that lmna, lmnb1, and lmnb2 genes of zebrafish are highly conservative and they may be homology of human LMNA, LMNB1 and LMNB2 genes. Conclusions Zebrafish lamins and human lamins have homologous sequence similarity, indicating that these two genes are orthologous genes.

LMNA- associated congenital muscular dystrophy：a case report and literature review / 临床儿科杂志

Objectives To explore the clinical features and diagnosis of LMNA-associated congenital muscular dystrophy. Methods The clinical data from a case of muscular dystrophy caused by LMNA gene mutation were retrospectively analyzed. The related literatures were reviewed. Results A 8-month-old female infant suffered from weakness of raising head, eyelid droop, and motor development retardtion. LMNA gene was sequenced for the infant, her parents and the older sister. Heterozygous mutation of c. 94_96 del AAG (p. K 32 del) was found in the infant leading to the diagnosis of LMNA- associated congenital muscular dystrophy. No mutation was found in the infant’s parents and her older sister. The literature review showed that all ofLMNA- associated congenital muscular dystrophy patients had LMNA gene mutation, more than 80% patients mainly presented with weakness of raising head and may accompany with weakness of proximal limb, motor development retardation, and weakness of axial muscle. Conclusions Mutation analysis of LMNA gene is conducive to the diagnosis of congenital muscular dystrophy.

Progeria: A rare genetic premature ageing disorder.

Progeria is characterized by clinical features that mimic premature ageing. Although the mutation responsible for this syndrome has been deciphered, the mechanism of its action remains elusive. Progeria research has gained momentum particularly in the last two decades because of the possibility of revealing evidences about the ageing process in normal and other pathophysiological conditions. Various experimental models, both in vivo and in vitro, have been developed in an effort to understand the cellular and molecular basis of a number of clinically heterogeneous rare genetic disorders that come under the umbrella of progeroid syndromes (PSs). As per the latest clinical trial reports, Lonafarnib, a farnesyltranferase inhibitor, is a potent ‘drug of hope’ for Hutchinson-Gilford progeria syndrome (HGPS) and has been successful in facilitating weight gain and improving cardiovascular and skeletal pathologies in progeroid children. This can be considered as the dawn of a new era in progeria research and thus, an apt time to review the research developments in this area highlighting the molecular aspects, experimental models, promising drugs in trial and their implications to gain a better understanding of PSs.

A family study of mandibuloacral dysplasia with type A lipodystrophy / 临床儿科杂志

Objective To study the gene mutations and clinical features of mandibuloacral dysplasia with type A lipodystrophy (MADA) in a Chinese family. Methods The information of 5 family members including 2 siblings suspected atyp-ical progeria was assembled. Genomic DNA was extracted from peripheral blood of 5 family members, the 12 exons of LMNA gene were ampliifed by PCR and then the PCR products were directly sequenced and analyzed by using Blast software online. The SIFT and PolyPhen-2 software were used to predict the harmfulness of mutations. Results The 2 siblings were clinically diagnosed as MADA. Heterozygous c.1579C>T (p.Arg527Cys) and c.1583C>T (p.Thr528Met) mutations were detected in this family. The father carried c.1583C>T (p.Thr528Met) mutation, the mother carried c.1579C>T (p.Arg527Cys) mutation, and their normal daughter were all heterozygous carriers with c.1583C>T (p.Thr528Met) mutation. Compound heterozygous c.1579C>T (p.Arg527Cys) and c.1583C>T (p.Thr528Met) mutations in 2 siblings led to MADA. The MADA showed an autosomal re-cessive inheritance pattern in this family. Conclusions The 2 siblings with MADA in this family were caused by compound heterozygous mutations in LMNA gene.

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.

Phenotype/genotype analysis of 4 cases of LMNA related congenital muscular dystrophy with inflammatory changes / 中华实用儿科临床杂志

Objective To analyze the clinical characteristics,muscle pathological features and pathogenic gene mutation in 4 cases with LMNA-related congenital muscular dystrophy (L-CMD).Methods Clinical data of the probands and the parents were collected.Skeletal muscle specimens were biopsied from the probands for pathological analysis.Genomic DNA and RNA were extracted from peripheral blood leukocytes,and PCR,reverse transcription(RT)-PCR and DNA direct sequencing were employed to analyze the LMNA gene to determine the gene mutation and confirm the pathogenicity.Results Four patients had symptoms from fetal period to several months after birth.They presented with motor retardation,muscle weakness with prominent the proximal upper limbs,distal lower limbs and neck extensor,hypotonia,contractures,with mild to moderate elevation of CK level.The muscle biopsies showed muscular dystrophic and with inflammatory changes,and the abnormal nuclear morphology was observed with transmission electron microscopy.Genetic analysis of them detected 4 dominant de novo mutations.Three of them had unreported pathogenic mutations.The same sites of the LMNA gene were wild type in their parents.Conclusions Four cases of L-CMD are genetically identified.Genetic counseling of the family can be possible.The patients should be considered LMNA gene mutation of they present themselves with muscle weakness with the proximal upper limbs,distal lower limbs and neck extensor,hypotonia,contractures,mild to moderate elevation of CK level,and if the biopsies show muscular dystrophic changes but also with inflammatory changes should be considered LMNA gene mutation.Genetic analysis is the most reliable method for diagnosing L-CMD.

A family with autosomal dominant Emery-Dreifuss muscular dystrophy and literature review / 中华实用儿科临床杂志

Objective To analyze the clinical characteristics,muscle pathological features and pathogenic gene mutation of a family with autosomal dominant Emery-Dreifuss muscular dystrophy (AD-EDMD).Methods Clinical data of the proband and her family members,a Chinese family of AD-EDMD,were collected.Skeletal muscle specimens were collected from the proband for pathological analysis.Genomic DNA from the proband and her parents was extracted using standard procedures from the peripheral blood leukocytes.PCR and DNA direct sequencing were employed to analyze all of the 12 exons of the LMNA gene to determine the gene mutation,and the case was summarized along with related literature review.Results The proband,female,4 years and 5 months old now,presented with muscle weakness during her early childhood,the proximally was more prominent,mild pectus excavatum.Her CK level was elevated,her electromyogram showed myogenic injuries,the muscle biopsy showed myopathy changes.Her father had the same symptom,with disease progressed,showed elbow contractures in early stage,stiff neck,tight achilles tendon,slowly progressive muscle weakness of the limbs,sinus bradycardia.A heterozygous missense mutation c.1580G ＞ C (p.Arg527Pro) was identified in exon 9 of the LMNA gene in the proband and her father,but not in her mother.This heterozygous missense mutation had been reported as a pathogenic gene mutation.Conclusions The patient who has elbow contractures in early stage,limited neck flexion,spine stiffness,muscle weakness with the proximal upper limbs and distal lower limbs,and arrhythmia,should have an analysis of the LMNA gene.It's important for the early diagnosis of EDMD,assessment of the prognosis,timely and effectively monitoring the changes of arrhythmia,then taking interventions to improve the quality of life and prolong life.So genetic analysis is most reliable method to diagnose EDMD.

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.