Novel partial loss-of-function variants in the tyrosyl-tRNA synthetase 1 (YARS1) gene involved in multisystem disease.

Cytoplasmic aminoacyl-tRNA synthetases (ARSs) are emerging as a cause of numerous rare inherited diseases. Recently, biallelic variants in tyrosyl-tRNA synthetase 1 (YARS1) have been described in ten patients of three families with multi-systemic disease (failure to thrive, developmental delay, liver dysfunction, and lung cysts). Here, we report an additional subject with overlapping clinical findings, heterozygous for two novel variants in tyrosyl-tRNA synthetase 1 (NM_003680.3(YARS1):c.176T>C; p.(Ile59Thr) and NM_003680.3(YARS1):c.237C>G; p.(Tyr79*) identified by whole exome sequencing. The p.Ile59Thr variant is located in the highly conserved aminoacylation domain of the protein. Compared to subjects previously described, this patient presents a much more severe condition. Our findings support implication of two novel YARS1 variants in these disorders. Furthermore, we provide evidence for a reduced protein abundance in cells of the patient, in favor of a partial loss-of-function mechanism.

Genetic Enteropathies Linked to Epithelial Structural Abnormalities and Enteroendocrine Deficiency: A Systematic Review.

OBJECTIVES: Congenital diarrhea and enteropathies linked to epithelial structural abnormalities constitute 3 different rare diseases: the tufting enteropathies (TE; EPCAM and SPINT2 mutations), microvillous inclusion disease (MVID; MYO5B and STX3 mutations), and tricho-hepato-enteric syndrome (THE; TTC37 and SKIV2L mutations). Moreover, enteroendocrine deficiencies (ED; PCSK1 and NEUROG3 mutations) share common clinical characteristics with TE, THE, and MVID in that the treatment requires, in most cases, long-term parenteral nutrition. Although numerous cases have been reported in the literature, aggregated data on morbidity and mortality are missing owing to the rarity of the diseases. METHODS: We performed a systematic review of all published cases and retrieved 86 articles describing 323 patients (164 boys and 135 girls). RESULTS: The mortality rate was 20.28%, with a median age at death of 13.5 months (range 0-228 months); the mortality risk was 30.8/1000 person-year; in half of the cases, death was caused by infections. Parenteral nutrition was required in 95.4% of patients and weaning off from parenteral nutrition was achieved in 29.35% at a median age of 23 months (range 3.3-276 months). The patients with ED linked to PCSK1 were nearly all weaned at a median age of 14 months, but most of the patients became overweight. MVID patients with MYO5B mutations were most often born preterm. ED linked to NEUROG3 mutation and THE patients usually presented with intrauterine growth retardation. CONCLUSIONS: This review presents data from 323 patients with congenital diarrhea linked to EPCAM TE, SPINT2 TE, TTC37 THE, SKIV2L THE, MYO5B MVID, STX3 MVID, NEUROG3 ED, and PCSK1 ED mutations.

A novel mutation of PCSK1 responsible for PC1/3 deficiency in two siblings.

Proprotein convertase 1 (PCSK1, PC1/3) deficiency is an uncommon cause of neonatal malabsorptive diarrhoea associated with endocrinopathies that are due to the disrupted processing of a large number of prohormones, including proinsulin. To date, only 26 cases have been reported. Herein, we describe two siblings with typical features including severe congenital diarrhoea, central diabetes insipidus, growth hormone deficiency, and hypoadrenalism. Next generation sequencing found a homozygous missense mutation in exon 5 of PCSK1 gene, c.500A>C (p.Asp167Ala), located within the catalytic domain. Both patients presented a high level of proinsulin. In the first years of life they required parenteral nutrition and hormone replacement therapy. The patients, aged 3 and 1.5 years, experienced several infectious episodes associated with septic shocks. While the mechanism underlying intestinal failure remains poorly investigated, parenteral nutrition is essential in order to ensure normal growth in early childhood.

A Rare Mutation in LMNB2 Associated with Lipodystrophy Drives Premature Cell Senescence.

Many proteins are causative for inherited partial lipodystrophies, including lamins, the essential constituents of the nuclear envelope scaffold called the lamina. By performing high throughput sequencing on a panel of genes involved in lipodystrophies, we identified a heterozygous mutation in LMNB2 gene (c.700C > T p.(Arg234Trp)) in a female patient presenting early onset type II diabetes, hypertriglyceridemia, and android fat distribution. This mutation is rare in the general population (frequency 0.013% in GnomAD) and was predicted pathogenic by a set of pathogenicity prediction software. Patient-derived fibroblasts showed nuclear shape abnormalities and premature senescence features, which are two typical cellular phenotypes associated with laminopathies. Moreover, we observed an atypical aggregation of lamin B2 in nucleoplasm, which co-distributes with emerin and lamin A/C, along with an abnormal distribution of lamin A/C at the nuclear envelope. Finally, reducing lamin B2 expression level by siRNA targeted toward LMNB2 transcripts resulted in decreased nuclear anomalies and senescence-associated beta-galactosidase, suggesting a role of the mutated protein in the occurrence of the observed cellular phenotype. Altogether, these results suggest that mutations in lamin B2 could produce premature senescence and partial lipodystrophy features as observed with certain mutants of lamin A/C.

Unraveling LMNA Mutations in Metabolic Syndrome: Cellular Phenotype and Clinical Pitfalls.

This study details the clinical and cellular phenotypes associated with two missense heterozygous mutations in LMNA, c.1745G > T p.(Arg582Leu), and c.1892G> A p.(Gly631Asp), in two patients with early onset of diabetes mellitus, hypertriglyceridemia and non-alcoholic fatty liver disease. In these two patients, subcutaneous adipose tissue was persistent, at least on the abdomen, and the serum leptin level remained in the normal range. Cellular studies showed elevated nuclear anomalies, an accelerated senescence rate and a decrease of replication capacity in patient cells. In cellular models, the overexpression of mutated prelamin A phenocopied misshapen nuclei, while the partial reduction of lamin A expression in patient cells significantly improved nuclear morphology. Altogether, these results suggest a link between lamin A mutant expression and senescence associated phenotypes. Transcriptome analysis of the whole subcutaneous adipose tissue from the two patients and three controls, paired for age and sex using RNA sequencing, showed the up regulation of genes implicated in immunity and the down regulation of genes involved in development and cell differentiation in patient adipose tissue. Therefore, our results suggest that some mutations in LMNA are associated with severe metabolic phenotypes without subcutaneous lipoatrophy, and are associated with nuclear misshaping.

High prevalence of mutations in perilipin 1 in patients with precocious acute coronary syndrome.

BACKGROUND AND AIMS: Genetic partial lipodystrophies are rare heterogeneous disorders characterized by abnormalities of fat distribution and associated metabolic complications including a predisposition for atherosclerotic cardiovascular disease. We hypothesized that the milder forms of these diseases might be underdiagnosed and might result in early acute coronary syndrome (ACS) as the first sign of the pathology. METHODS: We performed targeted sequencing on a panel of 8 genes involved in genetic lipodystrophy for 62 patients with premature ACS, and selected heterozygous missense variations with low frequency. To confirm those results, we analyzed a second independent group of 60 additional patients through Sanger sequencing, and compared to a control group of 120 healthy patients. RESULTS: In the first cohort, only PLIN1 exhibited variants in more than 1 patient. In PLIN1, 3 different variants were found in 6 patients. We then analyzed PLIN1 sequence in the second cohort with premature ACS and found 2 other patients. Altogether, 8 patients were carriers of 4 different mutations in PLIN1. The variant frequencies in the total cohort of 122 patients were compared to frequencies observed in a local control cohort and in 2 different public databases showing a significant difference between patient vs control group frequencies for two mutations out of 4 (c.245C > T p = 10-4; c.839G > A p = 0.014). DISCUSSION: This is the first study that identifies a high frequency of potential pathogenic mutations in PLIN1 related to early onset ACS. These findings could contribute to the prevention and care of precocious ACS in families carrying those mutations.

Congenital Sodium Diarrhea by mutation of the SLC9A3 gene.

Congenital Sodium Diarrhea (CSD) due to SLC9A3 mutation is a rare cause of neonatal diarrhea explained by dysfunction of the Na+/H+ antiporter 3 in intestine. To date only 10 patients have been described. We report a male patient with typical antenatal symptoms (polyhydramnios and intestinal dilation) and neonatal diarrhea with fecal sodium and bicarbonates loss. Next generation sequencing revealed a missense homozygous mutation in exon 6 of the SLC9A3 gene (NM_004174.3:c.1039G > A, NP_004165.2:p.Glu347Lys). Oral electrolytes supplements (Sodium and Bicarbonates) allowed a normal growth to the child currently aged twenty months. CSD symptomatology usually begins during third trimester of pregnancy. Antenatal signs are polyhydramnios and diffuse intestinal dilation. Main differential diagnoses are intestinal obstruction and Congenital Chloride Diarrhea. Diarrhea begins from the first days of life and its severity is variable. Based on the report and on the literature we suggest that non syndromic CSD can be detected during third trimester of pregnancy. With adequate electrolytes supplementation good evolution is possible.

Combined Immunodeficiency in Patients With Trichohepatoenteric Syndrome.

The syndromic diarrhea/trichohepatoenteric syndrome (SD/THE) is a rare and multi-system genetic disorder caused by mutation in SKIV2L or in TTC37, two genes encoding subunits of the putative human SKI complex involved in RNA degradation. The main features are intractable diarrhea of infancy, hair abnormalities, facial dysmorphism, and intrauterine growth restriction. Immunologically this syndrome is associated with a hypogammaglobulinemia leading to an immunoglobulin supplementation. Our immune evaluation of a large French cohort of SD/THE patient revealed several immunological defects. First, switched memory B lymphocytes count is very low. Second, IFN-γ production by T and NK cells is impaired and associated with a reduced degranulation of NK cells. Third, T cell proliferation was abnormal in 3/6 TTC37-mutated patients. These three patients present with severe EBV infection and a transient hemophagocytosis which may be related to these immunological defects. Moreover, an immunological screening of patients with clinical features of SD/THE could facilitate both diagnosis and therapeutic management of these patients.

The involvement of the nuclear lamina in human and rodent spermiogenesis: a systematic review.

The nuclear lamina (NL) is a filamentous protein meshwork, composed essentially of lamins, situated between the inner nuclear membrane and the chromatin. The NL is a component of the nuclear envelope, interacts with a wide range of proteins and is required for normal nuclear structure and physiological development. During spermiogenesis the spermatid nucleus is elongated, and dramatically reduced in size with protamines replacing histones to produce a highly compacted chromatin. There is mounting evidence from studies in human and rodent, that the NL plays an important role in mammalian spermatid differentiation during spermiogenesis. In this review, we summarize and discuss the data available in the literature regarding the involvement of lamins and their direct or indirect partners in normal and abnormal human spermiogenesis.

La lamina nucléaire (LN) est un réseau de filaments protéiques, composé essentiellement de lamines, situé entre la membrane nucléaire interne et la chromatine. La LN est un composant de l'enveloppe nucléaire, interagit avec une large gamme de protéines et est nécessaire à l'intégrité de la structure nucléaire et au développement physiologique. Au cours de la spermiogenèse, le noyau de la spermatide s'allonge et sa taille est considérablement réduite, les protamines remplaçant les histones dans le but de constituer une chromatine fortement compactée. De nombreux travaux chez l'homme et chez les rongeurs montrent que la LN joue un rôle important dans la différenciation des spermatides chez les mammifères au cours de la spermiogenèse. Dans cette revue, nous résumons et discutons les données disponibles dans la littérature concernant l'implication des lamines et de leurs partenaires directs ou indirects dans la spermiogenèse humaine normale et anormale.

Tricho-Hepato-Enteric Syndrome mutation update: Mutations spectrum of TTC37 and SKIV2L, clinical analysis and future prospects.

Tricho-Hepato-Enteric syndrome (THES) is a very rare autosomal recessive syndromic enteropathy caused by mutations of either TTC37 or SKIV2L genes. Very little is known of these two gene products in mammals nor of the pathophysiology of the disease. Since the identification of the genes, we have set up the molecular diagnostic of THES in routine, gathering a large cohort with clinical and molecular data. Here, we report the phenotype and genotype analysis of this cohort together with an extensive literature review of THES cases worldwide, that is, 96 individuals harboring mutations in one gene or the other. We set up locus-specific databases for both genes and reviewed the type of mutation as well as their localization in the proteins. No hot spot is evidenced for any type of mutation. The phenotypic analysis was first made on the whole cohort but is limited due to heterogeneity in clinical descriptions. We then examined the lab diagnostic cohort in detail for clinical manifestations. For the first time, we are able to suggest that patients lacking SKIV2L seem more severely affected than those lacking TTC37, in terms of liver damage and prenatal growth impairment.

A new mutation in the C-terminal end of TTC37 leading to a mild form of syndromic diarrhea/tricho-hepato-enteric syndrome in seven patients from two families.

Syndromic diarrhea/tricho-hepato-enteric syndrome (SD/THE) is a rare congenital enteropathy with seven main clinical features: intractable diarrhea of infancy, hair abnormalities, intrauterine growth restriction (IUGR), facial dysmorphism, immune dysfunction, and liver and skin abnormalities. SD/THE is caused by mutations in TTC37 or SKIV2L, two genes encoding components of the human SKI complex. To date, approximately 50 SD/THE patients have been described with a wide spectrum of mutations, and only one recurrent mutation has been identified in independent families. We present a detailed description of seven patients of Turkish origin with the same new mutation in TTC37: c.4572 G>A p.(Trp1524X). All seven patients were homozygous for this mutation and presented the typical clinical features of SD/THE, but with a milder presentation than usual. All seven patients were alive at the last follow-up. Four out of seven patients had no IUGR, and four patients never required parenteral nutrition. All patients presented a better growth rate than previously described in patients with SD/THE, with 4/7 above the 3rd percentile. The mutation is localized only forty amino acids from the end of TTC37, and as TTC37 is longer than the yeast SKI3, it is possible that a truncated protein is expressed and plays a reduced role in the SKI complex.

Loss-of-Function Mutations in UNC45A Cause a Syndrome Associating Cholestasis, Diarrhea, Impaired Hearing, and Bone Fragility.

Despite the rapid discovery of genes for rare genetic disorders, we continue to encounter individuals presenting with syndromic manifestations. Here, we have studied four affected people in three families presenting with cholestasis, congenital diarrhea, impaired hearing, and bone fragility. Whole-exome sequencing of all affected individuals and their parents identified biallelic mutations in Unc-45 Myosin Chaperone A (UNC45A) as a likely driver for this disorder. Subsequent in vitro and in vivo functional studies of the candidate gene indicated a loss-of-function paradigm, wherein mutations attenuated or abolished protein activity with concomitant defects in gut development and function.

Management of syndromic diarrhea/tricho-hepato-enteric syndrome: A review of the literature.

Syndromic diarrhea/tricho-hepato-enteric syndrome (SD/THE) is a rare disease linked to the loss of function of either TTC37 or SKIV2L, two components of the SKI complex. It is characterized by a combination of 9 signs (intractable diarrhea, hair abnormalities, facial dysmorphism, immune abnormalities, IUGR/SGA, liver abnormalities, skin abnormalities, congenital heart defect and platelet abnormalities). We present a comprehensive review of the management of SD/THE and tested therapeutic regimens. A review of the literature was conducted in May 2017: 29 articles and 2 abstracts were included describing a total of 80 patients, of which 40 presented with mutations of TTC37, 14 of SKIV2L. Parenteral nutrition was used in the management of 83% of the patients and weaned in 44% (mean duration of 14.97 months). Immunoglobulins were used in 33 patients, but data on efficacy was reported for 6 patients with a diminution of infection (n = 3) or diarrhea reduction (n = 2). Antibiotics (n = 11) provided no efficacy. Steroids (n = 17) and immunosuppressant drugs (n = 13) were used with little efficacy and mostly in patients with IBD-like SD/THE. Hematopoietic stem cell transplantation (HSCT) was performed in 4 patients: 2 died, for one it corrected the immune defects but not the other features and for the last one, it provided only a partial improvement. Finally, no specific diet was effective except for some contradictory reports for elemental formula. In conclusion, the management of SD/THE mainly involves parenteral nutrition and immunoglobulin supplementation. Antibiotics, steroids, immunosuppressants, and HSCT are not recommended as principle treatments since there is no evidence of efficacy.

Abnormal retention of nuclear lamina and disorganization of chromatin-related proteins in spermatozoa from DPY19L2-deleted globozoospermic patients.

The aim of this study was to characterize the nuclear lamina (NL) and lamin chromatin-partners in spermatozoa from four DPY19L2-deleted globozoospermic patients. We tested for spermatid transcripts encoding lamins and their chromatin-partners emerin, LAP2α, BAF and BAF-L, by reverse transcriptase-PCR using spermatozoa RNA. We also determined the localization of lamin B1, BAF and BAF-L by immunofluorescent analysis of spermatozoa from all patients. In RNA from globozoospermic and control spermatozoa we detected transcripts encoding lamin B1, lamin B3, emerin, LAP2α and BAF-L, but not A-type lamins. In contrast, BAF transcripts were detected in globozoospermic but not control spermatozoa. The NL was immature in human globozoospermic spermatozoa: lamin B1 signal was detected in the nuclei of globozoospermic spermatozoa in significantly higher proportions than the control (P < 0.05; 56-91% versus 40%) and was predominantly observed at the whole nuclear periphery, not polarized as in control spermatozoa. Conversely, BAF and BAF-L were detected in control, but not globozoospermic spermatozoa. Our results strongly emphasize the importance of the NL and associated proteins during human spermiogenesis. In globozoospermia, the lack of maturation of the NL, and the modifications in expression and location of chromatin-partners, could explain the chromatin defects observed in this rare phenotype.

LEM-domain proteins are lost during human spermiogenesis but BAF and BAF-L persist.

During spermiogenesis the spermatid nucleus is elongated, and dramatically reduced in size with protamines replacing histones to produce a highly compacted chromatin. After fertilisation, this process is reversed in the oocyte to form the male pronucleus. Emerging evidence, including the coordinated loss of the nuclear lamina (NL) and the histones, supports the involvement of the NL in spermatid nuclear remodelling, but how the NL links to the chromatin is not known. In somatic cells, interactions between the NL and the chromatin have been demonstrated: LEM-domain proteins and LBR interact with the NL and respectively, the chromatin proteins BAF and HP1. We therefore sought to characterise the lamina-chromatin interface during spermiogenesis, by investigating the localisation of six LEM-domain proteins, two BAF proteins and LBR, in human spermatids and spermatozoa. Using RT-PCR, IF and western blotting, we show that six of the proteins tested are present in spermatids: LEMD1, LEMD2 (a short isoform), ANKLE2, LAP2ß, BAF and BAF-L, and three absent: Emerin, LBR and LEMD3. The full-length LEMD2 isoform, required for nuclear integrity in somatic cells, is absent. In spermatids, no protein localised to the nuclear periphery, but five were nucleoplasmic, receding towards the posterior nuclear pole as spermatids matured. Our study therefore establishes that the lamina-chromatin interface in human spermatids is radically distinct from that defined in somatic cells. In ejaculated spermatozoa, we detected only BAF and BAF-L, suggesting that they might contribute to the shaping of the spermatozoon nucleus and, after fertilisation, its transition to the male pronucleus.

Differential Brain, Cognitive and Motor Profiles Associated with Partial Trisomy. Modeling Down Syndrome in Mice.

We hypothesize that the trisomy 21 (Down syndrome) is the additive and interactive outcome of the triple copy of different regions of HSA21. Because of the small number of patients with partial trisomy 21, we addressed the question in the Mouse in which three chromosomal regions located on MMU10, MMU17 and MMU16 carries almost all the HSA21 homologs. Male mice from four segmental trisomic strains covering the D21S17-ETS2 (syntenic to MMU16) were examined with an exhaustive battery of cognitive tests, motor tasks and MRI and compared with TS65Dn that encompasses D21S17-ETS2. None of the four strains gather all the impairments (measured by the effect size) of TS65Dn strain. The 152F7 strain was close to TS65Dn for motor behavior and reference memory and the three other strains 230E8, 141G6 and 285E6 for working memory. Episodic memory was impaired only in strain 285E6. The hippocampus and cerebellum reduced sizes that were seen in all the strains indicate that trisomy 21 is not only a hippocampus syndrome but that it results from abnormal interactions between the two structures.

IBD-Like Features in Syndromic Diarrhea/Trichohepatoenteric Syndrome.

BACKGROUND: Very early onset inflammatory bowel disease (VEOIBD) (inflammatory bowel disease [IBD] before 6 years of age) may manifest as a monogenic disease affecting the gastrointestinal tract. Syndromic diarrhea/trichohepatoenteric syndrome (SD/THE), a rare disorder caused by alteration of a complex involved in RNA degradation, has been reported to present with some degree of colitis and in some cases an IBD-like presentation. METHODS: We reviewed clinical and biological data of 4 previously published cases and added detailed data of 2 new cases of SD/THE with an IBD-like presentation. RESULTS: All the 6 patients presented with typical intractable diarrhea and hair abnormalities. The colon was affected in all of the patients: 1 had ileitis, 2 had panenteritis, and 2 presented with perianal disease. Fecal calprotectin level and erythrosedimentation rate were elevated in 2 cases each. All the therapeutic classes of IBD treatment (mesalazine, steroids, immunomodulators, and biological therapy) were used in the 6 cases. In 2 patients, treatment had no effect. Three showed a partial effect, and 1 patient sustained only a transient effect. CONCLUSIONS: SD/THE can have a similar presentation as VEOIBD, often as pancolitis. IBD treatments appear to have little efficacy for SD/THE, suggesting a different pathogenesis for the IBD-like features in SD/THE compared with classical IBD.

A Heterozygous ZMPSTE24 Mutation Associated with Severe Metabolic Syndrome, Ectopic Fat Accumulation, and Dilated Cardiomyopathy.

ZMPSTE24 encodes the only metalloprotease, which transforms prelamin into mature lamin A. Up to now, mutations in ZMPSTE24 have been linked to Restrictive Dermopathy (RD), Progeria or Mandibulo-Acral Dysplasia (MAD). We report here the phenotype of a patient referred for severe metabolic syndrome and cardiomyopathy, carrying a mutation in ZMPSTE24. The patient presented with a partial lipodystrophic syndrome associating hypertriglyceridemia, early onset type 2 diabetes, and android obesity with truncal and abdominal fat accumulation but without subcutaneous lipoatrophy. Other clinical features included acanthosis nigricans, liver steatosis, dilated cardiomyopathy, and high myocardial and hepatic triglycerides content. Mutated fibroblasts from the patient showed increased nuclear shape abnormalities and premature senescence as demonstrated by a decreased Population Doubling Level, an increased beta-galactosidase activity and a decreased BrdU incorporation rate. Reduced prelamin A expression by siRNA targeted toward LMNA transcripts resulted in decreased nuclear anomalies. We show here that a central obesity without subcutaneous lipoatrophy is associated with a laminopathy due to a heterozygous missense mutation in ZMPSTE24. Given the high prevalence of metabolic syndrome and android obesity in the general population, and in the absence of familial study, the causative link between mutation and phenotype cannot be formally established. Nevertheless, altered lamina architecture observed in mutated fibroblasts are responsible for premature cellular senescence and could contribute to the phenotype observed in this patient.

Prelamin A accumulation in endothelial cells induces premature senescence and functional impairment.

BACKGROUND: Defects in lamin A maturation result in premature aging syndromes and severe atherosclerosis as observed in the Hutchinson-Gilford Progeria Syndrome. In age-related atherosclerosis, several features of cellular senescence have been characterized in endothelial cells including telomere shortening and increased oxidative stress. However, to date, very little is known about lamin A alterations in these cells. OBJECTIVES: To study lamin A-related senescence and its consequences in the activation status of primary endothelial cells. METHODS: Healthy primary endothelial cells and progenitors issued from human umbilical vein or cord blood were used. Lamin A defects were induced by protease inhibitor (Atazanavir) treatment for 48 h. RESULTS: We show that protease inhibitor treatment leads to the accumulation of farnesylated prelamin A, inducing nuclear shape abnormalities and premature senescence in both differentiated and progenitor endothelial cells. ICAM-1-dependent activation and monocytes adhesion was increased in mature endothelial cells. In parallel, the ability to generate microvascular networks in matrigel was decreased for endothelial progenitors. The effects of protease inhibitor treatment on nuclear shapes were reversed when cells were treated in combination with Pravastatin and Zoledronate in both mature and progenitor endothelial cells. Reversion was also demonstrated with a morpholino antisense-oligonucleotide targeting lamin A-specific splice site. DISCUSSION: This study shows that protease inhibitor treatment reproduces premature senescence due to lamin A defects in primary endothelial cells and progenitors after 48 h exposure. The cells used were non-aged as extracted from cord blood or umbilical vein, allowing one to consider that other senescence pathways were not activated and that the observed alterations were specific of prelamin A accumulation. Both mature endothelial cells and precursors were sensitive to prelamin accumulation and thus, could be used in the future as a valuable model to test different approaches aimed at specifically reversing lamin A-related cells senescence.