Features of musculoskeletal apparatus and bone tissue in patients with premature aging syndromes

Aim. Аnalysis and synthesis of the literature data on the problem of differential diagnosis of neonatal progeroid syndrome. Key points. One of the rarest representatives of premature aging syndromes is neonatal progeroid syndrome (Wiedemann–Rautenstrauch syndrome). It is an ultra-orphan disease with autosomal recessive type of inheritance, associated with a mutation in the POLR3A, POLR3B, POLR3GL genes and characterized by congenital lipodystrophy and premature aging. The disease manifests from the first days of life: low body length and weight at birth, pronounced phenotypic features (pseudohydrocephaly, progeroid facial features, generalized lipodystrophy, neonatal incisors). Severe bronchopulmonary and skeletal damage is seen over the course of life, and average life expectancy ranges from 7 months to 2 years but can reach 27 years. The differential diagnosis is made with Hutchinson–Gilford syndrome (progeria), which clinical signs manifest at 1.5-2 years of age, and with Marfan-progeroid lipodystrophy, Fontaine syndrome, and Sekkel syndrome. Conclusion. Early diagnostics is necessary for predicting the course of the disease, selection of treatment, and determining of further management. Keywords: neonatal progeroid syndrome, Wiedemann–Rautenstrauch syndrome, premature aging syndromes

The neonatal progeroid syndrome (Wiedemann–Rautenstrauch): A model for the study of human aging?

Синдром Видемана-Раутенштрауха (неонатальный прогероидный синдром) — ультраорфанное заболевание из группы синдромов преждевременного старения с аутосомно-рецессивным типом наследования, ассоциированный с мутациями в генах POLR3A, POLR3B и POLR3GL, кодирующих РНК-полимеразу III. Частота заболевания в настоящее время неизвестна. Мы представляем первое в Российской Федерации клиническое описание пациента 7 лет 6 месяцев с синдромом Видемана-Раутенштрауха (компаунд-гетерозиготные мутации в гене POLR3A) с прогероидными чертами, адентией, задержкой роста (SDS роста -3,41, SDS скорости роста -2,47), дефицитом массы тела (SDS ИМТ -6,20) и генерализованной липодистрофией. В статье представлено наблюдение пациента на протяжении 1,5 года, рассмотрен мировой опыт динамического наблюдения пациентов с неонатальным прогероидным синдромом, дифференциальная диагностика, а также даны рекомендации по ведению пациентов с данным заболеванием. Учитывая отсутствие на сегодняшний день специфического лечения, пациенты наблюдаются многопрофильной командой врачей.

Induced pluripotent stem cells (iPSCs) derived from patients with premature aging disorders are widely regarded as a foundation for both the study of fundamental aging mechanisms and preclinical testing of anti-aging therapies. The most well-studied is Hutchinson-Gilford progeria syndrome (HGPS), which is caused by a lamin A gene mutation. Comparing the progeroid phenotype in cell models of distinct premature aging syndromes is critical for identifying early and common aging hallmarks. In this study, using a non-integrative episomal approach we reprogrammed iPSCs from cells of a patient suffering from Wiedemann-Rautenstrauch Syndrome (WRS), which is caused by bi-allelic pathogenic mutations of the RNA polymerase III subunit A gene (POLR3A). In parallel, an iPSC line with the classic HGPS caused by a lamin A mutation was obtained. HGPS and WRS patient fibroblasts showed similar signs of cellular aging; however, unlike HGPS, the causal link between the premature aging phenotype and WRS driving mutations is unclear. RNA polymerase III is required for the transcription of small nuclear RNAs and being a target of TORC1 (Target of Rapamycin kinase Complex 1), it plays a role in longevity and aging in model organisms. Whereas lamin A is downregulated in iPSCs, allowing for regeneration of HGPS iPSCs, we found that POLR3A is upregulated during reprogramming. Enhanced expression of mutant POLR3A in WRS iPSCs led to nucleolus abnormalities and telomerase RNA component (TERC) sequestration in the nucleoli in WRS iPSCs. WRS iPSCs may be an important model for developing new therapeutic approaches affecting premature aging of stem cells.

Lamins are nuclear intermediate filament proteins. They provide mechanical stability, organize chromatin and regulate transcription, replication, nuclear assembly and nuclear positioning. Recent studies provide new insights into the role of lamins in development, differentiation and tissue response to mechanical, reactive oxygen species and thermal stresses. These studies also propose the existence of separate filament networks for A- and B-type lamins and identify new roles for the different networks. Furthermore, they show changes in lamin composition in different cell types, propose explanations for the more than 14 distinct human diseases caused by lamin A and lamin C mutations and propose a role for lamin B1 in these diseases.

Objective To assess clinicopathological features of and genetic factors in Hutchinson-Gilford progeria syndrome（HGPS）in a family. Methods General information was collected from 3 patients with Hutchinson-Gilford progeria syndrome in a family, which included 5 members over 2 generations with all the 3 children affected by HGPS. All the 3 patients underwent clinical investigation, image analysis of hands, lungs and mandibles, as well as karyotype analysis of chromosomes. LMNA gene mutations were analyzed in these family members. Results All the 3 patients developed skin sclerosis with severe growth retardation and appearance of extreme aging at about 6 months of age. Image analysis showed osteoporosis and mandibular hypoplasia in the elder patient. Karyotype analysis showed no abnormality in the patients or their parents. Mutation analysis revealed a homozygous mutation 1579 C > T（R527C）in exon 9 of the LMNA gene in all the patients, but a heterozygous mutation R527C in the LMNA gene in their parents. Conclusions The patients in this family present characteristic manifestations of HGPS, which may be caused by the homozygous LMNA mutation R527C. Key words: Progeria; LMNA gene; DNA mutational analysis; Hutchinson-Gilford syndrome

Bi-allelic pathogenic variations within POLR3A have been associated with a spectrum of hereditary disorders. Among these, a less frequently observed condition is Wiedemann–Rautenstrauch syndrome (WRS), also known as neonatal progeroid syndrome. This syndrome typically manifests neonatally and is characterized by growth retardation, evident generalized lipodystrophy with distinctively localized fat accumulations, sparse scalp hair, and atypical facial features. Our objective was to elucidate the underlying molecular mechanisms of Wiedemann–Rautenstrauch syndrome (WRS). In this study, we present a clinical case of a 7-year-old female patient diagnosed with WRS. Utilizing whole-exome sequencing (WES), we identified a novel missense variant c.3677T>C (p.Leu1226Pro) in the POLR3A gene (NM_007055.4) alongside two cis intronic variants c.1909+22G>A and c.3337-11T>C. Via the analysis of mRNA derived from fibroblasts, we reconfirmed the splicing-affecting nature of the c.3337-11T>C variant. Furthermore, our investigation led to the reclassification of the c.3677T>C (p.Leu1226Pro) variant as a likely pathogenic variant. Therefore, this is the first case demonstrating the molecular genetics of a patient with Wiedemann–Rautenstrauch syndrome from the Russian Federation. A limited number of clinical cases have been documented until this moment; therefore, broadening the linkage between phenotype and molecular changes in the POLR3A gene will significantly contribute to the comprehensive understanding of the molecular basis of POLR3A-related disorders.

141st ENMC International Workshop Inaugural Meeting of the EURO-Laminopathies Project Nuclear Envelope-linked Rare Human Diseases: From Molecular Pathophysiology towards Clinical Applications 10–12 March 2006, Naarden, The Netherlands

Identification of mitochondrial dysfunction in Hutchinson–Gilford progeria syndrome through use of stable isotope labeling with amino acids in cell culture

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. Key words: Hutchinson-Gilford Progeria syndrome; LMNA gene; Progeria

Aging is a universal and inevitable process that affects virtually all living organisms; in humans, aging is characterized by a gradual decline of physical and psychological functions that ultimately leads to death. Over the past decades, the study of progeroid syndromes, a group of premature aging disorders that recapitulates multiple features of physiological aging, has provided insightful information toward the identification of mechanisms underlying aging. In this chapter, we provide an updated description of the main progeroid syndromes affecting humans, including their clinical manifestations and the genetic and molecular basis underlying their pathogenesis. Most progeroid syndromes originate from defective DNA repair and nuclear structure systems, highlighting a key role of genome stability in aging. A special emphasis is given to Hutchinson Gilford Progeria Syndrome (HGPS), the most well-studied premature aging disorder, which is characterized by accelerated aging and early death due to cardiovascular complications. HGPS is typically caused by a silent mutation in the LMNA gene that provokes the expression of progerin, a dominant-negative mutant protein that anchors aberrantly to the nuclear envelope, thereby inducing cellular toxicity and organismal detriment. Thus, we provide a description of established cellular and animal models for HGPS and discuss the perspectives for therapeutic developments, including an updated presentation of treatment strategies that have been tested so far in vitro (human HGPS fibroblast cultures) and in vivo (HGPS mice models) and in clinical trials, with argumentation of their main limitations.

Hutchinson–Gilford Progeria syndrome (HGPS) serves as a prominent model for Progeroid syndromes, a group of rare genetic disorders characterized by accelerated aging. This review explores the genetic basis, clinical presentation, and complications of HGPS. HGPS is caused by mutations in the LMNA gene, resulting in the production of a defective structural protein, prelamin A. This protein contains a “CAAX” motif, where C represents cysteine, and its abnormal processing is central to the disease’s pathology. HGPS leads to multiple organ systems being affected, including cardiovascular, skeletal, neurological, and dermatological systems, causing severe disability and increased mortality. Cardiovascular issues are particularly significant in HGPS and are crucial for developing therapeutic strategies. Recent advances in treatment modalities offer promise for managing HGPS. Farnesyltransferase inhibitors and genetic interventions, such as CRISPR-Cas9, have shown potential in mitigating progerin-associated symptoms, with encouraging results observed in preclinical and clinical studies. Additionally, emerging therapies such as rapamycin, sulforaphane, and MG132 hold promise in targeting underlying disease mechanisms. Comprehensive management approaches, including growth hormone therapy, retinoids, and dental care, are emphasized to enhance overall patient well-being. Despite progress, further research is essential to unravel the complex pathophysiology of Progeroid syndromes and develop effective treatments. Continued focus on therapies that address progerin accumulation and its downstream effects is vital for improving patient care and outcomes for individuals affected by HGPS and related disorders. This review highlights ongoing efforts to understand and combat Progeroid syndromes, aiming to alleviate the burdens imposed by these debilitating conditions.

Neonatal progeroid syndrome or Wiedemann-Rautenstrauch syndrome (WRS; MIM 264090) is a rare genetic disorder that has clinical symptoms including premature aging, lipodystrophy, and variable mental impairment. Until recently genetic background of the disease was unclear. However, recent studies have indicated that WRS patients have compound heterozygote variations in the POLR3A (RNA polymerase III subunit 3A; MIM 614258) gene that might be responsible for the disease phenotype. In this study we report a WRS patient that has compound heterozygote variations in the POLR3A gene. One of the reported variations in our patient, c.3568C>T, p.(Gln1190Ter), is a novel variation that was not reported before. The other variant, c.3337-11T>C, was previously shown in WRS patients in trans with other variations.

Hutchinson-Gilford progeria syndrome (HGPS) is one of the most severe disorders among laminopathies—a heterogeneous group of genetic diseases with a molecular background based on mutations in the LMNA gene and genes coding for interacting proteins. HGPS is characterized by the presence of aging-associated symptoms, including lack of subcutaneous fat, alopecia, swollen veins, growth retardation, age spots, joint contractures, osteoporosis, cardiovascular pathology, and death due to heart attacks and strokes in childhood. LMNA codes for two major, alternatively spliced transcripts, give rise to lamin A and lamin C proteins. Mutations in the LMNA gene alone, depending on the nature and location, may result in the expression of abnormal protein or loss of protein expression and cause at least 11 disease phenotypes, differing in severity and affected tissue. LMNA gene-related HGPS is caused by a single mutation in the LMNA gene in exon 11. The mutation c.1824C > T results in activation of the cryptic donor splice site, which leads to the synthesis of progerin protein lacking 50 amino acids. The accumulation of progerin is the reason for appearance of the phenotype. In this review, we discuss current knowledge on the molecular mechanisms underlying the development of HGPS and provide a critical analysis of current research trends in this field. We also discuss the mouse models available so far, the current status of treatment of the disease, and future prospects for the development of efficient therapies, including gene therapy for HGPS.

Progeroid syndromes are rare genetic disorders that impact patients' health and lifespans and are characterized by symptoms that mimic the normal aging process. Telomere length is one of the aging hallmarks, a phenomenon linked to cellular aging. Telomere attrition was observed in different progeroid syndromes, such as Nijmegen breakage syndrome patients and Werner syndrome, indicating its contribution to the progeroid phenotype. However, whether it is a common feature in all progeroid syndromes is still unclear. Therefore, in this study, we aimed to estimate telomere length using the DNA methylation-based estimator of human telomere length in publicly available DNA methylation data from patients with Werner Syndrome, Hutchinson-Gilford Progeria Syndrome, Berardinelli-Seip Congenital Lipodystrophy type 2, and Dyskeratosis congenita, along with additional data provided by our laboratory from patients with Cerebroretinal Microangiopathy with Calcifications and Cysts and Wiedemann-Rautenstrauch Syndrome. Our findings revealed that certain progeroid syndromes, including classical Werner Syndrome, Berardinelli-Seip Congenital Lipodystrophy type 2, and Dyskeratosis congenita, have significant telomere attrition conversely to Hutchinson-Gilford Progeria Syndrome, Cerebroretinal Microangiopathy with Calcifications and Cysts, Wiedemann-Rautenstrauch Syndrome, and atypical Werner Syndrome. In conclusion, this study addresses a critical gap by providing new insights into the role of telomere attrition across different progeroid conditions. Further research is needed to elucidate the effect of telomere attrition on progeroid syndromes and its implications.