First Japanese case of atypical progeroid syndrome/atypical Werner syndrome with heterozygous LMNA mutation

Clinical Spectrum of LMNA-Associated Type 2 Familial Partial Lipodystrophy: A Systematic Review

Type 2 familial partial lipodystrophy (FPLD2) is a laminopathic lipodystrophy due to pathogenic variants in the LMNA gene. Its rarity implies that it is not well-known. The aim of this review was to explore the published data regarding the clinical characterisation of this syndrome in order to better describe FPLD2. For this purpose, a systematic review through a search on PubMed until December 2022 was conducted and the references of the retrieved articles were also screened. A total of 113 articles were included. FPLD2 is characterised by the loss of fat starting around puberty in women, affecting limbs and trunk, and its accumulation in the face, neck and abdominal viscera. This adipose tissue dysfunction conditions the development of metabolic complications associated with insulin resistance, such as diabetes, dyslipidaemia, fatty liver disease, cardiovascular disease, and reproductive disorders. However, a great degree of phenotypical variability has been described. Therapeutic approaches are directed towards the associated comorbidities, and recent treatment modalities have been explored. A comprehensive comparison between FPLD2 and other FPLD subtypes can also be found in the present review. This review aimed to contribute towards augmenting knowledge of the natural history of FPLD2 by bringing together the main clinical research in this field.

Case report: Focal segmental glomerulosclerosis in a pediatric atypical progeroid syndrome

Atypical progeroid syndrome (APS) is a rare type of progeroid syndrome mainly caused by heterozygous missense mutations in the LMNA (MIM 150330) gene. APS has heterogeneous clinical manifestations, and its kidney manifestations, particularly in children, are rarely documented. Here, we report the first pediatric case of APS with focal segmental glomerulosclerosis (FSGS). A 10-year-old boy with progeroid features was referred to the nephrology clinic because of hyperuricemia. He had dark skin, protruding eyes, and beaked nose and was very thin, suggesting lipodystrophy. He had been treated for recurrent urinary tract infection during infancy, and liver biopsy for persisting hepatitis showed steatohepatitis. He also had hypertrophic cardiomyopathy (HCMP) with mitral and tricuspid valve regurgitation. Genetic studies were performed considering his multisystem symptoms, and he was diagnosed as having APS according to exome sequencing findings (c.898G > C, p.Asp300His of LMNA). During the first visit to the nephrology clinic, he had minimal proteinuria (urine protein/creatinine ratio of 0.23 mg/mg), which worsened during follow-up. In three years, his urine protein/creatinine ratio and N-acetyl-b-D-glucosaminidase/creatinine ratio increased to 1.52 and 18.7, respectively. The kidney biopsy result was consistent with findings of FSGS, peri-hilar type, showing segmental sclerosis of 1 (5%) glomerulus out of 21 glomeruli. An angiotensin receptor blocker was added to manage his proteinuria. This is the first pediatric report of FSGS in an APS patient with confirmed LMNA defect, who manifested progeroid features, lipodystrophy, HCMP with heart valve dysfunction, and steatohepatitis. Our case suggests that screening for proteinuric nephropathy is essential for managing APS patients since childhood.

Long-term survival in a patient with Hutchinson-Gilford progeria syndrome and osteosarcoma: A case report

BACKGROUND

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare disease characterized by the rapid appearance of aging with an onset in childhood. Serious cardiovascular complications can be life-threatening events for affected patients and the cause of early death. Herein we report a HGPS patient with osteosarcoma hat was successfully managed and is alive 13 years after the diagnosis. This is the first report describing the detailed surgical procedure and long-term follow-up of osteosarcoma in a patient with HGPS.

CASE SUMMARY

The patient was diagnosed with HGPS at 5 years of age with typical features and was referred to our department with a suspected bone tumor of the left proximal tibia at the age of 18. Open biopsy of the tibial bone tumor revealed a conventional fibroblastic osteosarcoma. We have developed and performed a freezing technique using liquid nitrogen for tumor reconstruction. This technique overcame the small size of the tibia for megaprosthesis and avoided amputation and limb salvage was achieved 13 years post-operatively. Although the patient had a number of surgical site complications, such as wound dehiscence, and superficial and deep infections due to vulnerable skin in HGPS, no recurrence or metastases were detected for 13 years, and she walks assisted by crutches. Her general health was good at the latest follow-up at 31 years of age.

CONCLUSION

A HGPS patient with osteosarcoma was successfully managed and she was alive 13 years after the diagnosis.

Hepatic Steatosis Resulting From LMNA-Associated Familial Lipodystrophy

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, with potential causes stemming from obesity, metabolic syndrome, genetic disorders, and drug toxicity. We report a 42-year-old woman with lipodystrophy and NAFLD due to a pathogenic variant in the LMNA (D300N) gene. This case report attempts to encourage clinicians to consider genetic diseases, specifically lipodystrophies, when working up uncommon causes of NAFLD.

Crucial Role of Lamin A/C in the Migration and Differentiation of MSCs in Bone

Lamin A/C, intermediate filament proteins from the nuclear lamina encoded by the LMNA gene, play a central role in mediating the mechanosignaling of cytoskeletal forces into nucleus. In fact, this mechanotransduction process is essential to ensure the proper functioning of other tasks also mediated by lamin A/C: the structural support of the nucleus and the regulation of gene expression. In this way, lamin A/C is fundamental for the migration and differentiation of mesenchymal stem cells (MSCs), the progenitors of osteoblasts, thus affecting bone homeostasis. Bone formation is a complex process regulated by chemical and mechanical cues, coming from the surrounding extracellular matrix. MSCs respond to signals modulating the expression levels of lamin A/C, and therefore, adapting their nuclear shape and stiffness. To promote cell migration, MSCs need soft nuclei with low lamin A content. Conversely, during osteogenic differentiation, lamin A/C levels are known to be increased. Several LMNA mutations present a negative impact in the migration and osteogenesis of MSCs, affecting bone tissue homeostasis and leading to pathological conditions. This review aims to describe these concepts by discussing the latest state-of-the-art in this exciting area, focusing on the relationship between lamin A/C in MSCs' function and bone tissue from both, health and pathological points of view.

Lamin A/C Mechanotransduction in Laminopathies

Mechanotransduction translates forces into biological responses and regulates cell functionalities. It is implicated in several diseases, including laminopathies which are pathologies associated with mutations in lamins and lamin-associated proteins. These pathologies affect muscle, adipose, bone, nerve, and skin cells and range from muscular dystrophies to accelerated aging. Although the exact mechanisms governing laminopathies and gene expression are still not clear, a strong correlation has been found between cell functionality and nuclear behavior. New theories base on the direct effect of external force on the genome, which is indeed sensitive to the force transduced by the nuclear lamina. Nuclear lamina performs two essential functions in mechanotransduction pathway modulating the nuclear stiffness and governing the chromatin remodeling. Indeed, A-type lamin mutation and deregulation has been found to affect the nuclear response, altering several downstream cellular processes such as mitosis, chromatin organization, DNA replication-transcription, and nuclear structural integrity. In this review, we summarize the recent findings on the molecular composition and architecture of the nuclear lamina, its role in healthy cells and disease regulation. We focus on A-type lamins since this protein family is the most involved in mechanotransduction and laminopathies.

DNA Damage Response/TP53 Pathway Is Activated and Contributes to the Pathogenesis of Dilated Cardiomyopathy Associated With LMNA (Lamin A/C) Mutations

RATIONALE

Mutations in the LMNA gene, encoding LMNA (lamin A/C), are responsible for laminopathies. Dilated cardiomyopathy (DCM) is a major cause of mortality and morbidity in laminopathies.

OBJECTIVE

To gain insights into the molecular pathogenesis of DCM in laminopathies.

METHODS AND RESULTS

We generated a tet-off bigenic mice expressing either a WT (wild type) or a mutant LMNA (D300N) protein in cardiac myocytes. LMNA^D300N mutation is associated with DCM in progeroid syndromes. Expression of LMNA^D300N led to severe myocardial fibrosis, apoptosis, cardiac dysfunction, and premature death. Administration of doxycycline suppressed LMNA^D300N expression and prevented the phenotype. Whole-heart RNA sequencing in 2-week-old WT and LMNA^D300N mice led to identification of ≈6000 differentially expressed genes. Gene Set Enrichment and Hallmark Pathway analyses predicted activation of E2F (E2F transcription factor), DNA damage response, TP53 (tumor protein 53), NFκB (nuclear factor κB), and TGFβ (transforming growth factor-β) pathways, which were validated by Western blotting, quantitative polymerase chain reaction of selected targets, and immunofluorescence staining. Differentially expressed genes involved cell death, cell cycle regulation, inflammation, and epithelial-mesenchymal differentiation. RNA sequencing of human hearts with DCM associated with defined LMNA pathogenic variants corroborated activation of the DNA damage response/TP53 pathway in the heart. Increased expression of CDKN2A (cyclin-dependent kinase inhibitor 2A)-a downstream target of E2F pathway and an activator of TP53-provided a plausible mechanism for activation of the TP53 pathway. To determine pathogenic role of TP53 pathway in DCM, Tp53 gene was conditionally deleted in cardiac myocytes in mice expressing the LMNA^D300N protein. Deletion of Tp53 partially rescued myocardial fibrosis, apoptosis, proliferation of nonmyocyte cells, left ventricular dilatation and dysfunction, and slightly improved survival.

CONCLUSIONS

Cardiac myocyte-specific expression of LMNA^D300N, associated with DCM, led to pathogenic activation of the E2F/DNA damage response/TP53 pathway in the heart and induction of myocardial fibrosis, apoptosis, cardiac dysfunction, and premature death. The findings denote the E2F/DNA damage response/TP53 axis as a responsible mechanism for DCM in laminopathies and as a potential intervention target.

Outcomes of 4 years of molecular genetic diagnosis on a panel of genes involved in premature aging syndromes, including laminopathies and related disorders

BACKGROUND

Segmental progeroid syndromes are a heterogeneous group of rare and often severe genetic disorders that have been studied since the twentieth century. These progeroid syndromes are defined as segmental because only some of the features observed during natural aging are accelerated.

METHODS

Since 2015, the Molecular Genetics Laboratory in Marseille La Timone Hospital proposes molecular diagnosis of premature aging syndromes including laminopathies and related disorders upon NGS sequencing of a panel of 82 genes involved in these syndromes. We analyzed the results obtained in 4 years on 66 patients issued from France and abroad.

RESULTS

Globally, pathogenic or likely pathogenic variants (ACMG class 5 or 4) were identified in about 1/4 of the cases; among these, 9 pathogenic variants were novel. On the other hand, the diagnostic yield of our panel was over 60% when the patients were addressed upon a nosologically specific clinical suspicion, excepted for connective tissue disorders, for which clinical diagnosis may be more challenging. Prenatal testing was proposed to 3 families. We additionally detected 16 variants of uncertain significance and reclassified 3 of them as benign upon segregation analysis in first degree relatives.

CONCLUSIONS

High throughput sequencing using the Laminopathies/ Premature Aging disorders panel allowed molecular diagnosis of rare disorders associated with premature aging features and genetic counseling for families, representing an interesting first-level analysis before whole genome sequencing may be proposed, as a future second step, by the National high throughput sequencing platforms ("Medicine France Genomics 2025" Plan), in families without molecular diagnosis.

Diabetes mellitus coexisted with progeria: a case report of atypical Werner syndrome with novel LMNA mutations and literature review

Werner syndrome (WS) is a rare, adult-onset progeroid syndrome. Classic WS is caused by WRN mutation and partial atypical WS (AWS) is caused by LMNA mutation. A 19-year-old female patient with irregular menstruation and hyperglycemia was admitted. Physical examination revealed characteristic faces of progeria, graying and thinning of the hair scalp, thinner and atrophic skin over the hands and feet, as well as lipoatrophy of the extremities, undeveloped breasts at Tanner stage 3, and short stature. The patient also suffered from severe insulin-resistant diabetes mellitus, hyperlipidemia, fatty liver, and polycystic ovarian morphology. Possible WS was considered and both WRN and LMNA genes were analyzed. A novel missense mutation p.L140Q (c.419T>A) in the LMNA gene was identified and confirmed the diagnosis of AWS. Her father was a carrier of the same mutation. We carried out therapy for lowering blood glucose and lipid and improving insulin resistance, et al. The fasting glucose, postprandial glucose and triglyceride level was improved after treatment for 9 days. Literature review of AWS was performed to identify characteristics of the disease. Diabetes mellitus is one of the clinical manifestations of WS and attention must give to the differential diagnosis. Gene analysis is critical in the diagnosis of WS. According to the literature, classic and atypical WS differ in incidence, pathogenic gene, and clinical manifestations. Characteristic dermatological pathology may be significantly more important for the initial identification of AWS. Early detection, appropriate treatments, and regular follow-up may improve prognosis and survival of WS patients.

Premature aging syndromes: From patients to mechanism

Aging is an inevitable consequence of human life resulting in a gradual deterioration of cell, tissue and organismal function and an increased risk to develop chronic ailments. Premature aging syndromes, also known as progeroid syndromes, recapitulate many clinical features of normal aging and offer a unique opportunity to elucidate fundamental mechanisms that contribute to human aging. Progeroid syndromes can be broadly classified into those caused by perturbations of the nuclear lamina, a meshwork of proteins located underneath the inner nuclear membrane (laminopathies); and a second group that is caused by mutations that directly impair DNA replication and repair. We will focus mainly on laminopathies caused by incorrect processing of lamin A, an intermediate filament protein that resides at the nuclear periphery. Hutchinson-Gilford Progeria (HGPS) is an accelerated aging syndrome caused by a mutation in lamin A and one of the best studied laminopathies. HGPS patients exhibit clinical characteristics of premature aging, including alopecia, aberrant pigmentation, loss of subcutaneous fat and die in their teens as a result of atherosclerosis and cardiovascular complications. Here we summarize how cell- and mouse-based disease models provided mechanistic insights into human aging and discuss experimental strategies under consideration for the treatment of these rare genetic disorders.

Inhibition of JAK-STAT Signaling with Baricitinib Reduces Inflammation and Improves Cellular Homeostasis in Progeria Cells

Hutchinson-Gilford progeria syndrome (HGPS), a rare premature aging disorder that leads to death at an average age of 14.7 years due to myocardial infarction or stroke, is caused by mutations in the LMNA gene. Nearly 90% of HGPS cases carry the G608G mutation within exon 11 that generates a truncated prelamin A protein “progerin”. Progerin accumulates in HGPS cells and induces premature senescence at the cellular and organismal levels. Children suffering from HGPS develop numerous clinical features that overlap with normal aging, including atherosclerosis, arthritis, hair loss and lipodystrophy. To determine whether an aberrant signaling pathway might underlie the development of these four diseases (atherosclerosis, arthritis, hair loss and lipodystrophy), we performed a text mining analysis of scientific literature and databases. We found a total of 17 genes associated with all four pathologies, 14 of which were linked to the JAK1/2-STAT1/3 signaling pathway. We report that the inhibition of the JAK-STAT pathway with baricitinib, a Food and Drug Administration-approved JAK1/2 inhibitor, restored cellular homeostasis, delayed senescence and decreased proinflammatory markers in HGPS cells. Our ex vivo data using human cell models indicate that the overactivation of JAK-STAT signaling mediates premature senescence and that the inhibition of this pathway could show promise for the treatment of HGPS and age-related pathologies.

Cerebral Haemorrhage in a Young Patient With Atypical Werner Syndrome Due to Mutations in LMNA

Introduction: Werner syndrome is a rare genetic disorder; classical Werner syndrome is caused by mutations in the WRN gene. However, recent research has shown that LMNA gene mutations can also cause premature ageing syndromes such as atypical Werner syndrome (AWS). AWS usually manifests as muscular damage, defects in the cardiac conduction system, lipoatrophy, diabetes, atherosclerosis, and premature ageing. Clinical presentation: A 24-year-old man presented with severe abdominal aortic and peripheral artery disease and cerebral haemorrhage. He was prescribed once-daily 20 mg atorvastatin. Another large cerebral haemorrhage occurred 8 months after discharge. Although he underwent minimally invasive intracranial haematoma surgery, paralysis set in. Molecular studies showed a missense mutation within exon 5 (c.898G>C) that caused amino acid aspartate 300 to be replaced by histidine (p.Asp300His) in the LMNA gene. The patient was diagnosed with AWS. Conclusions: Haemorrhagic stroke and progeroid features may be manifestations of LMNA-linked AWS. In such cases, the patient's family history and genetic background should be investigated. WRN and LMNA gene testing of the proband and the immediate family should be considered. This case report provides a deeper understanding of the role of LMNA mutations in AWS.

Bone mineral density in familial partial lipodystrophy

OBJECTIVE

Type 1 and type 2 familial partial lipodystrophies (FPLD) are characterized by the loss or increase in subcutaneous fat in certain body regions, as well as metabolic disorders. Higher muscle volume and mass have also been described. However, so far, possible bone involvement has not been studied. The aim of this study was to evaluate bone mineral density (BMD) in patients with type 1 and type 2 FPLD.

METHODS

A total of 143 women were selected and distributed into three groups (17 women with FPLD2, 82 women with FPLD1 and 44 nonlipodystrophic obese female controls). A thorough history and physical examination were carried out on all subjects, as well as the measurement of anthropometric features. BMD along with fat and fat-free mass (FFM) were determined by DXA (dual-energy X-ray absorptiometry). Statistical analyses, primarily using the χ² , ANOVA and ANCOVA tests, were performed, using age, height, fat and FFM as covariables.

RESULTS

After eliminating the possible influences of age, height, fat and FFM, we observed that there were no significant differences in total BMD between patients with FPLD and the control group, showing total BMD values of 1.092 ± 0.037 g/cm² in the FPLD2 group, 1.158 ± 0.013 g/cm² in the FPLD1 group and 1.173 ± 0.018 g/cm² in the control group (P = .194). Similarly, no significant differences were found in segmental BMD.

CONCLUSIONS

Unlike in other types of laminopathy in which bone is affected, in the case of FPLD, there are no differences in BMD compared to nonlipodystrophic subjects.

Lipodystrophic laminopathies: Diagnostic clues

The nuclear lamina is a complex reticular structure that covers the inner face of the nucleus membrane in metazoan cells. It is mainly formed by intermediate filaments called lamins, and exerts essential functions to maintain the cellular viability. Lamin A/C provides mechanical steadiness to the nucleus and regulates genetic machinery. Laminopathies are tissue-specific or systemic disorders caused by variants in LMNA gene (primary laminopathies) or in other genes encoding proteins which are playing some role in prelamin A maturation or in lamin A/C function (secondary laminopathies). Those disorders in which adipose tissue is affected are called laminopathic lipodystrophies and include type 2 familial partial lipodystrophy and certain premature aging syndromes. This work summarizes the main clinical features of these syndromes, their associated comorbidities and the clues for the differential diagnosis with other lipodystrophic disorders.

Association of serum levels of antibodies against MMP1, CBX1, and CBX5 with transient ischemic attack and cerebral infarction

Transient ischemic attack (TIA) is a predictor for cerebral infarction (CI), and early diagnosis of TIA is extremely important for the prevention of CI. We set out to identify novel antibody biomarkers for TIA and CI, and detected matrix metalloproteinase 1 (MMP1), chromobox homolog 1 (CBX1), and chromobox homolog 5 (CBX5) as candidate antigens using serological identification of antigens by recombinant cDNA expression cloning (SEREX) and Western blotting to confirm the presence of serum antibodies against the antigens. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) revealed that serum antibody levels were significantly higher in patients with TIA or acute-phase CI (aCI) compared with healthy donors (P < 0.01). Spearman’s correlation analysis and multivariate logistic regression analysis demonstrated that levels of anti-MMP1, anti-CBX1, and anti-CBX5 antibodies were associated with age, cigarette-smoking habits, and blood pressure. Thus, serum levels of antibodies against MMP1, CBX1, and CBX5 could potentially serve as useful tools for diagnosing TIA and predicting the onset of aCI.

Non-syndromic cardiac progeria in a patient with the rare pathogenic p.Asp300Asn variant in the LMNA gene

Background

Mutations in LMNA gene, encoding Lamin A/C, cause a diverse array of phenotypes, collectively referred to as laminopathies. The most common manifestation is dilated cardiomyopathy (DCM), occurring in conjunction with variable skeletal muscle involvement but without involvement of the coronary arteries. Much less commonly, LMNA mutations cause progeroid syndromes, whereby an early-onset coronary artery disease (CAD) is the hallmark of the disease. We report a hitherto unreported compound cardiac phenotype, dubbed as “non-syndromic cardiac progeria”, in a young patient who carried a rare pathogenic variant in the LMNA gene and developed progressive degeneration of various cardiac structures, as seen in the elderly. The phenotype resembled the progeroid syndromes, except that it was restricted to the heart and did not involve other organs.

Case presentation

The patient was a well-developed Caucasian female who presented at age 29 years with an acute myocardial infarction (MI) and was found to have extensive CAD. She had none of the conventional risk factors for atherosclerosis. She underwent coronary artery bypass surgery but continued to require multiple percutaneous coronary interventions for symptomatic obstructive coronary lesions. During the course of next 10 years, she developed mitral regurgitation, degenerative mitral and aortic valve diseases, atrial flutter, and progressive conduction defects. She died from progressive heart failure with predominant involvement of the right ventricle and severe tricuspid regurgitation. Cardiac phenotype in this young patient resembled degenerative cardiac diseases of the elderly and the progeroid syndromes. However, in contrast to the progeroid syndromes, the phenotype was restricted to the heart and did not involve other organs. Thus, the phenotype was dubbed as a non-syndromic cardiac progeria.

Genetic screening of several cardiomyopathy genes, including LMNA, which is a causal gene for progeroid syndromes, led to identification of a very rare pathogenic p.Asp300Asn variant in the LMNA gene.

Conclusions

We infer that the LMNA p.Asp300Asn mutation is pathogenic in non-syndromic cardiac progeria. Mutations involving codon 300 in the LMNA gene have been associated with progeroid syndromes involving multiple organs. Collectively, the data provide credence to the causal role of p.Asp300Asn mutation in the pathogenesis of non-syndromic cardiac progeria.

Electronic supplementary material

The online version of this article (10.1186/s12881-017-0480-x) contains supplementary material, which is available to authorized users.

Genomic diagnosis by whole genome sequencing in a Korean family with atypical progeroid syndrome

Clinical genomic diagnosis is unfamiliar to many dermatologists. Limited knowledge of bioinformatics has limited the use of the next generation sequencing method in dermatological clinics. We evaluated the usefulness of whole genome sequencing as a diagnostic approach to inherited dermatological disease. Here, we present our experience with two female siblings with atypical familial generalized lipodystrophy with diabetes mellitus and dyslipidemia. Whole genome sequencing was performed to diagnose the inherited disease. We compared control genomic databases using the Exome Aggregation Consortium, and filtered false-positive calls with the segmental duplication, non-flagged single nucleotide variants and COSMIC mutation databases, and applied the prediction tools of SIFT and PolyPhen2. The two siblings who presented with generalized lipodystrophy were diagnosed with an atypical progeroid syndrome with a p.D136H mutation in the LMNA gene (NM_005572). We diagnosed a familial atypical progeroid syndrome using whole genome sequencing. In this paper, we present our experience with whole genome sequencing and demonstrate that it can provide useful information for clinical genomic diagnosis of inherited diseases with atypical clinical features, such as atypical progeroid syndrome.