Temperature-dependent autoactivation associated with clinical variability of PDGFRB Asn666 substitutions.

Ocular pterygium-digital keloid dysplasia (OPDKD) presents in childhood with ingrowth of vascularized connective tissue on the cornea leading to severely reduced vision. Later the patients develop keloids on digits but are otherwise healthy. The overgrowth in OPDKD affects body parts that typically have lower temperature than 37°C. We present evidence that OPDKD is associated with a temperature sensitive, activating substitution, p.(Asn666Tyr), in PDGFRB. Phosphorylation levels of PDGFRB and downstream targets were higher in OPDKD fibroblasts at 37°C but were further greatly increased at the average corneal temperature of 32°C. This suggests that the substitution cause significant constitutive autoactivation mainly at lower temperature. In contrast, a different substitution in the same codon, p.(Asn666Ser), is associated with Penttinen type of premature aging syndrome. This devastating condition is characterized by widespread tissue degeneration, including pronounced chronic ulcers and osteolytic resorption in distal limbs. In Penttinen syndrome fibroblasts, equal and high levels of phosphorylated PDGFRB was present at both 32°C and 37°C. This indicates that this substitution causes severe constitutive autoactivation of PDGFRB regardless of temperature. In line with this, most downstream targets were not affected by lower temperature. However, STAT1, important for tissue wasting, did show further increased phosphorylation at 32°C. Temperature-dependent autoactivation offers an explanation to the strikingly different clinical outcomes of substitutions in the Asn666 codon of PDGFRB.

An additional case of Néstor-Guillermo progeria syndrome diagnosed in early childhood.

Néstor-Guillermo progeria syndrome (NGPS; OMIM 614008) is characterized by early onset and slow progression of symptoms including poor growth, lipoatrophy, pseudosenile facial appearance, and normal cognitive development. In contrast to other progeria syndromes, NGPS is associated with a longer lifespan and higher risk for developing severe skeletal abnormalities. It is an autosomal recessive condition caused by biallelic pathogenic variants in BANF1. There are two previously reported patients with NGPS, both Spanish with molecular diagnoses made in adulthood and having the same homozygous pathogenic variant c.34G > A; p.Ala12Thr. Presented here is a 2 year, 8 month old girl with short stature, poor weight gain, sparse hair, and dysmorphic facial features reminiscent of premature aging. Whole exome sequencing identified the same c.34G > A homozygous pathogenic variant in BANF1 as reported in the previous patients. This is the first reported case of a child and is supporting evidence for this recurrent loss of function variant.

Ultrasonic Characteristics of Cardiovascular Changes in Children with Hutchinson-Gilford Progeria Syndrome: A Comparative Study with Normal Children and Aging People.

BACKGROUND: The cardiovascular characteristics of children with Hutchinson-Gilford progeria syndrome (HGPS) remain unclear. The present study is aimed at evaluating the cardiovascular changes with ultrasound examination in children with HGPS and compared these with those in normal children and older people. METHODS: Seven HGPS children, 21 age-matched healthy children, and 14 older healthy volunteers were evaluated by three-dimensional echocardiography (including strain analysis) and carotid elasticity examination with the echo-tracking technique. RESULTS: Children with HGPS had higher left ventricular ejection fraction (LVEF) and global longitudinal strain, when compared to older healthy volunteers (P < 0.05). However, these parameters were not significantly different, when compared to those in healthy children. Furthermore, children with HGPS had lower average peak times in the left ventricle, when compared with the other two groups. For the structure of the carotid artery detected by ultrasound, the abnormality rates were similar between children with HGPS and older healthy volunteers (83.3% vs. 71.4%). The elastic parameters, elastic modulus, stiffness parameter, and pulsed wave transmittal velocity of children with HGPS were lower, when compared to those in older healthy volunteers (P < 0.05), while they were higher with arterial compliance (P > 0.05). Furthermore, no significant difference existed among the vascular elastic parameters between HGPS and normal children. CONCLUSION: HGPS children had impaired left ventricular (LV) synchrony, when compared to normal children, although the difference in LVEF was not statistically significant. Furthermore, the structural abnormality of the carotid artery in HGPS children was similar to that in older people, although the index of elasticity appears to be more favorable. These results suggest that the cardiovascular system in HGPS children differs from natural aging.

Hutchinson-Gilford Progeria Syndrome and Severe Aortic Stenosis: A New Hope for Treatment.

Hutchinson-Gilford progeria syndrome is an autosomal dominant, rare, fatal pediatric segmental premature aging disease. Cardiovascular and cerebrovascular diseases constitute the major cause of morbidity and mortality. Patients with the syndrome and severe aortic valve stenosis have been described in the literature, and for all of them a strategy of conservative management has been followed. We describe the first successful treatment of a 23-year-old Hutchinson-Gilford progeria syndrome patient with severe aortic stenosis who underwent transapical transcatheter aortic valve replacement.

Skeletal maturation and long-bone growth patterns of patients with progeria: a retrospective study.

BACKGROUND: Hutchinson-Gilford progeria syndrome (termed progeria in this Article) is a rare sporadic genetic disorder. One early clinical manifestation of progeria is abnormal skeletal growth, yet this growth has not been fully characterised. We aimed to characterise the skeletal maturation and long-bone growth patterns of patients with the clinical phenotype of progeria. METHODS: For this retrospective study, we reviewed skeletal surveys of patients (aged <20 years) with progeria obtained over a 9·5-year period. Most surveys included radiographs of the hands and long bones (humeri, radii, ulnas, tibias, and fibulas). Bone ages of these patients were estimated by the standards of Greulich and Pyle. Following the established methods for studying long-bone growth, the study cohort was separated into two overlapping age groups: longitudinal bone length measurements were made between physes for the childhood group (aged 12 years or younger) and from the upper margins of the proximal to the lower margin of the distal ossified epiphyses for the adolescent group (aged 10 years or older). Bone age estimates and bone length measurements were plotted against the chronological age of patients and compared with reference standards. Statistical analyses were based on mixed models. FINDINGS: 85 patients with progeria and 250 skeletal surveys were included in our study. For both sexes, bone age estimates showed a more advanced skeletal maturation rate throughout all chronological ages than the normal rate of 1 (p<0·0001), with the rate of maturation being 1·09 (SE 0·02) for boys and 1·14 (0·02) for girls. Longitudinal long-bone lengths began to deviate from normal standards by age 1-2 years. Growth curves for these long bones plateaued at about half the normal eventual bone length, and the half-life (the time taken to grow to half the eventual bone length) was also about half the time compared with normal standards. INTERPRETATION: Our study established growth curves that might serve as reference standards for skeletal maturation and long-bone growth of patients with the clinical phenotype of progeria. FUNDING: The Progeria Research Foundation, the US National Heart, Lung and Blood Institute, the Dana-Farber Cancer Institute Stop&Shop Pediatric Brain Tumor Program, the US National Center for Research Resources, US National Institutes of Health.

Extraskeletal Calcifications in Hutchinson-Gilford Progeria Syndrome.

PURPOSE: Children with Hutchinson-Gilford progeria syndrome (HGPS), a rare premature aging disease, exhibit extraskeletal calcifications detected by radiographic analysis and on physical examination. The aim of this study was to describe the natural history and pathophysiology of these abnormal calcifications in HGPS, and to determine whether medications and/or supplements tested in clinical trials alter their development. METHODS: Children from two successive clinical trials administering 1) lonafarnib (n = 26) and 2) lonafarnib + pravastatin + zoledronic acid (n = 37) were studied at baseline (pre-therapy), one year on therapy, and at end-of-therapy (3.3-4.3 years after the baseline visit). Calcium supplementation (oral calcium carbonate) was administered during the first year of the second trial and was subsequently discontinued. Information on calcifications was obtained from physical examinations, radiographs, and serum and urinary biochemical measures. The mineral content of two skin-derived calcifications was determined by x-ray diffraction. RESULTS: Extraskeletal calcifications were detected radiographically in 12/39 (31%) patients at baseline. The odds of exhibiting calcifications increased with age (p = 0.045). The odds were unaffected by receipt of lonafarnib, pravastatin, and zoledronate therapies. However, administration of calcium carbonate supplementation, in conjunction with all three therapeutic agents, significantly increased the odds of developing calcifications (p = 0.009), with the odds plateauing after the supplement's discontinuation. Composition analysis of calcinosis cutis showed hydroxyapatite similar to bone. Although serum calcium, phosphorus, and parathyroid hormone (PTH) were within normal limits at baseline and on-therapy, PTH increased significantly after lonafarnib initiation (p < 0.001). Both the urinary calcium/creatinine ratio and tubular reabsorption of phosphate (TRP) were elevated at baseline in 22/39 (56%) and 31/37 (84%) evaluable patients, respectively, with no significant changes while on-therapy. The mean calcium × phosphorus product (Ca × Pi) was within normal limits, but plasma magnesium decreased over both clinical trials. Fibroblast growth factor 23 (FGF23) was lower compared to age-matched controls (p = 0.03). CONCLUSIONS: Extraskeletal calcifications increased with age in children with HGPS and were composed of hydroxyapatite. The urinary calcium/creatinine ratio and TRP were elevated for age while FGF23 was decreased. Magnesium decreased and PTH increased after lonafarnib therapy which may alter the ability to mobilize calcium. These findings demonstrate that children with HGPS with normal renal function and an unremarkable Ca × Pi develop extraskeletal calcifications by an unidentified mechanism that may involve decreased plasma magnesium and FGF23. Calcium carbonate accelerated their development and is, therefore, not recommended for routine supplementation in these children.

A rare male patient with Fontaine progeroid syndrome caused by p.R217H de novo mutation in SLC25A24.

We report the clinical and genetic findings in a 15-year-old Spanish boy presenting prenatal and postnatal growth retardation, reduced subcutaneous adipose tissue, premature skin wrinkling, sparse hair, short distal phalanges with small nails, umbilical hernia, wide anterior fontanel, and normal cognitive and motor development. Exome sequencing uncovered a heterozygous mutation in SLC25A24 (NM_013386: c.650G>A: p.R217H) that encodes for the calcium-binding mitochondrial carrier protein SCaMC-1. This gain-of-function variant has been previously associated with Fontaine syndrome and Gorlin-Chaudhry-Moss syndrome, two entities that show overlapping features, and have been recently subsumed under the name Fontaine progeroid syndrome (FPS; MIM: 612289) in OMIM. Here, we describe the first male patient with genetically confirmed FPS who survives at least until adolescence.

Assessment of the Aging of the Brown Adipose Tissue by 18F-FDG PET/CT Imaging in the Progeria Mouse Model Lmna-/.

Brown adipose tissue (BAT) is an important energy metabolic organ that is highly implicated in obesity, type 2 diabetes, and atherosclerosis. Aging is one of the most important determinants of BAT activity. In this study, we used 18F-FDG PET/CT imaging to assess BAT aging in Lmna-/- mice. The maximum standardized uptake value (SUVMax) of the BAT was measured, and the target/nontarget (T/NT) values of BAT were calculated. The transcription and the protein expression levels of the uncoupling protein 1 (UCP1), beta3-adrenergic receptor (ß3-AR), and the PR domain-containing 16 (PRDM16) were measured by quantitative real-time polymerase chain reaction (RT-PCR) and Western blotting or immunohistochemical analysis. Apoptosis and cell senescence rates in the BAT of WT and Lmna-/- mice were determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and by CDKN2A/p16INK4a immunohistochemical staining, respectively. At 14 weeks of age, the BAT SUVMax and the expression levels of UCP1, ß3-AR, and PRDM16 in Lmna-/- mice were significantly reduced relative to WT mice. At the same time, the number of p16INK4a and TUNEL positively stained cells (%) increased in Lmna-/- mice. Collectively, our results indicate that the aging characteristics and the aging regulatory mechanism in the BAT of Lmna-/- mice can mimic the normal BAT aging process.

Progeria: an extremely unusual disorder.

Hutchinson-Gilford progeria syndrome, also known as progeria, is an extremely rare disorder with an incidence rate of 1 in 8 million. It occurs sporadically, and patients suffering from this syndrome usually exhibit premature ageing. It has an autosomal recessive inheritance with a slight male predominance. The affected children usually die early with an average life span of 13.4 years. The most common cause of death in such patients is a cardio-vascular abnormality such as myocardial infarction. We present a rare case of progeria in an 8-year-old boy who was diagnosed clinically and was referred to our department for a skeletal survey. Almost all of the typical radiological findings were present in this case, which further confirmed the clinical diagnosis of progeria.

Sporadic premature aging in a Japanese monkey: a primate model for progeria.

In our institute, we have recently found a child Japanese monkey who is characterized by deep wrinkles of the skin and cataract of bilateral eyes. Numbers of analyses were performed to identify symptoms representing different aspects of aging. In this monkey, the cell cycle of fibroblasts at early passage was significantly extended as compared to a normal control. Moreover, both the appearance of senescent cells and the deficiency in DNA repair were observed. Also, pathological examination showed that this monkey has poikiloderma with superficial telangiectasia, and biochemical assay confirmed that levels of HbA1c and urinary hyaluronan were higher than those of other (child, adult, and aged) monkey groups. Of particular interest was that our MRI analysis revealed expansion of the cerebral sulci and lateral ventricles probably due to shrinkage of the cerebral cortex and the hippocampus. In addition, the conduction velocity of a peripheral sensory but not motor nerve was lower than in adult and child monkeys, and as low as in aged monkeys. However, we could not detect any individual-unique mutations of known genes responsible for major progeroid syndromes. The present results indicate that the monkey suffers from a kind of progeria that is not necessarily typical to human progeroid syndromes.

A prospective study of radiographic manifestations in Hutchinson-Gilford progeria syndrome.

BACKGROUND: Progeria is a rare segmental premature aging disease with significant skeletal abnormalities. Defining the full scope of radiologic abnormalities requires examination of a large proportion of the world's progeria population (estimated at 1 in 4 million). There has been no comprehensive prospective study describing the skeletal abnormalities associated with progeria. OBJECTIVE: To define characteristic radiographic features of this syndrome. MATERIALS AND METHODS: Thirty-nine children with classic progeria, ages 2-17 years, from 29 countries were studied at a single site. Comprehensive radiographic imaging studies were performed. RESULTS: Sample included 23 girls and 16 boys-the largest number of patients with progeria evaluated prospectively to date. Eight new and two little known progeria-associated radiologic findings were identified (frequencies of 3-36%). Additionally, 23 commonly reported findings were evaluated. Of these, 2 were not encountered and 21 were present and ranked according to their frequency. Nine abnormalities were associated with increasing patient age (P = 0.02-0.0001). CONCLUSION: This study considerably expands the radiographic morphological spectrum of progeria. A better understanding of the radiologic abnormalities associated with progeria and improved understanding of the biology of progerin (the molecule responsible for this disease), will improve our ability to treat the spectrum of bony abnormalities.

Clinical imaging findings in a girl with Hutchinson-Gilford progeria syndrome.

We report an 82-year-old girl with premature aging, a karyotype of 46,XX and a de novo c.1824C>T mutation encoding p.G608G in the lamin A gene. The clinical features of accelerated aging and the molecular finding were consistent with the diagnosis of Hutchinson-Gilford progeria syndrome (HGPS). In this presentation, we demonstrate the radiological imaging findings of skeletal, oral and craniofacial phenotypes of abnormalities associated with HGPS. The oral and craniofacial abnormalities caused dental caries, severe malocclusion, and swallowing, feeding and speech problems. Dural calcification, and granulation in the ear drum and external ear canal were additionally observed.

Hip pathology in Hutchinson-Gilford progeria syndrome: a report of two children.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder. The estimated incidence is one in 4 million births. Orthopaedic manifestations include abnormality of the hips occurring early in the disease process. Severe coxa valga can be apparent by the age of 2 years. We report two cases of HGPS, one in a 7-year-old girl with avascular necrosis of the left hip and the second in a 13-year-old girl with recurrent traumatic hip dislocations. We demonstrate the pathoanatomical changes in the hip with HGPS using a combination of imaging modalities including radiographic, computed tomographic and MRI scans. These include coxa magna, coxa valga and acetabular dysplasia. We also comment on how these would affect the surgical management of this high-risk group of patients.

Craniofacial abnormalities in Hutchinson-Gilford progeria syndrome.

HGPS is a rare syndrome of segmental premature aging. Our goal was to expand the scope of structural bone and soft-tissue craniofacial abnormalities in HGPS through CT or MR imaging. Using The Progeria Research Foundation Medical and Research Database, 98 imaging studies on 25 patients, birth to 14.1 years of age, were comprehensively reviewed. Eight newly identified abnormalities involving the calvaria, skull base, and soft tissues of the face and orbits were present with prevalences between 43% and 100%. These included J-shaped sellas, a mottled appearance and increased vascular markings of the calvaria, abnormally configured mandibular condyles, hypoplastic articular eminences, small zygomatic arches, prominent parotid glands, and optic nerve kinking. This expanded craniofacial characterization helps link disease features and improves our ability to evaluate how underlying genetic and cellular abnormalities culminate in a disease phenotype.

Estimation of vessel age and early diagnose of atherosclerosis in progeria syndrome by using echo-tracking.

The stiffness of the arteries normally increases with age. Radiofrequency echo-tracking is a non-invasive ultrasound method which is able to detect the stiffness of the arteries, represented by the beta stiffness index. The estimation of biological age of vessels is possible on the basis of the normal age-group specific beta stiffness values. The beta stiffness index becomes higher in early stages of atherosclerosis as well, before any visible morphological changes. Hutchinson-Gilford progeria syndrome (HGPS) is rare genetic disorder resulting in accelerated aging including appearance of progressive atherosclerosis at an early age which determines the quality and term of life of these patients. Determination of vascular age and early diagnosis of atherosclerosis seems crucial. According to our knowledge, the estimation of vascular age detected with radiofrequency echo-tracking in HGPS patients, in contrast to the normal age-specific beta stiffness values, has not been published yet.

Atypical progeroid syndrome due to heterozygous missense LMNA mutations.

CONTEXT: Hutchinson-Gilford progeria syndrome (HGPS) and mandibuloacral dysplasia are well-recognized allelic autosomal dominant and recessive progeroid disorders, respectively, due to mutations in lamin A/C (LMNA) gene. Heterozygous LMNA mutations have also been reported in a small number of patients with a less well-characterized atypical progeroid syndrome (APS). OBJECTIVE: The objective of the study was to investigate the underlying genetic and molecular basis of the phenotype of patients presenting with APS. RESULTS: We report 11 patients with APS from nine families, many with novel heterozygous missense LMNA mutations, such as, P4R, E111K, D136H, E159K, and C588R. These and previously reported patients now reveal a spectrum of clinical features including progeroid manifestations such as short stature, beaked nose, premature graying, partial alopecia, high-pitched voice, skin atrophy over the hands and feet, partial and generalized lipodystrophy with metabolic complications, and skeletal anomalies such as mandibular hypoplasia and mild acroosteolysis. Skin fibroblasts from these patients when assessed for lamin A/C expression using epifluorescence microscopy revealed variable nuclear morphological abnormalities similar to those observed in patients with HGPS. However, these nuclear abnormalities in APS patients could not be rescued with 48 h treatment with farnesyl transferase inhibitors, geranylgeranyl transferase inhibitors or trichostatin-A, a histone deacetylase inhibitor. Immunoblots of cell lysates from fibroblasts did not reveal prelamin A accumulation in any of these patients. CONCLUSIONS: APS patients have a few overlapping but some distinct clinical features as compared with HGPS and mandibuloacral dysplasia. The pathogenesis of clinical manifestations in APS patients seems not to be related to accumulation of mutant farnesylated prelamin A.

A farnesyltransferase inhibitor improves disease phenotypes in mice with a Hutchinson-Gilford progeria syndrome mutation.

Hutchinson-Gilford progeria syndrome (HGPS) is caused by the production of a truncated prelamin A, called progerin, which is farnesylated at its carboxyl terminus. Progerin is targeted to the nuclear envelope and causes misshapen nuclei. Protein farnesyltransferase inhibitors (FTI) mislocalize progerin away from the nuclear envelope and reduce the frequency of misshapen nuclei. To determine whether an FTI would ameliorate disease phenotypes in vivo, we created gene-targeted mice with an HGPS mutation (LmnaHG/+) and then examined the effect of an FTI on disease phenotypes. LmnaHG/+ mice exhibited phenotypes similar to those in human HGPS patients, including retarded growth, reduced amounts of adipose tissue, micrognathia, osteoporosis, and osteolytic lesions in bone. Osteolytic lesions in the ribs led to spontaneous bone fractures. Treatment with an FTI increased adipose tissue mass, improved body weight curves, reduced the number of rib fractures, and improved bone mineralization and bone cortical thickness. These studies suggest that FTIs could be useful for treating humans with HGPS.