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

Variants in FREM1 and trisomy 18 identified in a neonatal progeria patient

BACKGROUND

Neonatal progeroid disorders are rare disorders with clinical features including low body mass index, proptosis, aged and dysmorphic facial features at the time of birth, prominent veins, sparse scalp hairs, and severe growth retardation. Very few cases have been identified with an unknown genetic cause. Here, we report clinical and genetic findings of a proband with hallmark features of neonatal progeria.

METHODS

Microarray comparative genomic hybridization, whole exome sequencing (WES) and Sanger sequencing were performed using standard methods.

RESULTS

Array combined genome hybridization data revealed trisomy 18 in the proband (II-1), and WES data identified novel compound heterozygous variants (c.247 C > T; p.H83Y and c.14769868InsA) in the FREM1 gene.

CONCLUSION

We report a novel complex case of neonatal progeria with atrial septal defects, trisomy 18 without typical features of Edward syndrome. The phenotype of the patient was more consistent with neonatal progeria, thus we speculate it to be caused by the FREM1 variants.

WIEDEMANN–RAUTENSTRAUCH SYNDROME: CASE REPORT

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Unique combination and in silico modeling of biallelic POLR3A variants as a cause of Wiedemann-Rautenstrauch syndrome

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.

Sclerodermalike syndromes: Great imitators

Sclerodermalike syndromes (SLSs) comprise diseases with mucin deposition (eg, scleromyxedema, scleredema), with eosinophilia (eg, eosinophilic fasciitis), metabolic or biochemical abnormalities (eg, nephrogenic systemic fibrosis), or endocrine disorders (eg, POEMS syndrome, or polyneuropathy, organomegaly, endocrinopathy, monoclonal lymphoproliferative disorder, and hypothyroidism). Chronic graft-versus-host disease may also show sclerodermalike skin changes. Inherited progeria syndromes with early aging (eg, Werner syndrome) and a heterogeneous group of hereditary disorders with either skin thickening (eg, stiff skin syndrome) or atrophy and tightening (eg, acrogeria) can also imitate classic systemic sclerosis (SSc). In addition, SLSs can be provoked by several drugs, chemicals, or even physical injury (eg, trauma, vibration stress, radiation). In SLSs, the distribution of skin involvement seems to be atypical compared with SSc. The acral skin involvement is usually missing, and lack of Raynaud phenomenon, scleroderma-specific antinuclear antibodies, the absence of scleroderma capillary pattern, and internal organ manifestations indicate the presence of an SLS. Skin involvement is sometimes nodular, and the underlying tissues can also be affected. For the differential diagnosis, a skin biopsy of the deeper layers including fascia and muscle is required. Histology does not always allow differentiation between SSc and SLSs; therefore, the diagnosis is often based on the distribution, quality of cutaneous involvement, and other accompanying clinical features.

Aging--RNA in development and disease

Given that RNA is involved in virtually all biological processes, it is perhaps not surprising that several RNA-binding proteins are associated with aging and with different age-related disorders. Other articles in this volume will discuss some specific examples of diseases where RNA plays a role that are also associated with aging, such as cancer and inflammation, so here I will discuss some general aspects of how RNA changes with the aging process. I will also discuss some specific examples of RNA-binding proteins that are associated with age-dependent neurological diseases as these provide an interesting framework to examine how lifetime mutations might lead to a late onset disease, although the answers to these questions are still not well understood.

Marfan syndrome with neonatal progeroid syndrome-like lipodystrophy associated with a novel frameshift mutation at the 3' terminus of the FBN1-gene

We report on a 25-year-old woman with pronounced generalized lipodystrophy and a progeroid aspect since birth, who also had Marfan syndrome (MFS; fulfilling the Ghent criteria) with mild skeletal features, dilated aortic bulb, dural ectasia, bilateral subluxation of the lens, and severe myopia in addition to the severe generalized lipodystrophy. She lacked insulin resistance, hypertriglyceridemia, hepatic steatosis, and diabetes. Mutation analysis in the gene encoding fibrillin 1 (FBN1) revealed a novel de novo heterozygous deletion, c.8155_8156del2 in exon 64. The severe generalized lipodystrophy in this patient with progeroid features has not previously been described in other patients with MFS and FBN1 mutations. We did not find a mutation in genes known to be associated with congenital lipodystrophy (APGAT2, BSCL2, CAV1, PTRF-CAVIN, PPARG, LMNB2) or with Hutchinson-Gilford progeria (ZMPSTE24, LMNA/C). Other progeria syndromes were considered unlikely because premature greying, hypogonadism, and scleroderma-like skin disease were not present. Our patient shows striking similarity to two patients who have been published in this journal by O'Neill et al. [O'Neill et al. (2007); Am J Med Genet Part A 143A:1421-1430] with the diagnosis of neonatal progeroid syndrome (NPS). This condition also known as Wiedemann-Rautenstrauch syndrome is a rare disorder characterized by accelerated aging and lipodystrophy from birth, poor postnatal weight gain, and characteristic facial features. The course is usually progressive with early lethality. However this entity seems heterogeneous. We suggest that our patient and the two similar cases described before represent a new entity, a subgroup of MFS with overlapping features to NPS syndrome.

Natural course of neonatal progeroid syndrome

BACKGROUND

Several progeroid disorders presenting a specific "old-man" appearance since birth or childhood have been described. Here, five patients with a history of severe intrauterine and postnatal growth retardation and pseudohydrocephaloid cranium noted after birth that were suggestive of neonatal progeroid syndrome (NPS) or Wiedemann-Rautenstrauch syndrome are reported. We discuss the natural course of the syndrome.

METHODS

A series of anthropometric measurements, imaging, dual energy X-ray absorptiometry, and endocrine investigations to assess metabolic complications such as hyperinsulinemia and dyslipidemia were performed on these five patients who were followed for 1-7 years. Screening of inborn errors, karyotyping, chromosomal breakage rates and DNA mutational studies with direct sequencing of LMNA, ERCC8 and ZMPSTE24 genes were also performed.

RESULTS

Generalized lipodystrophy was noted in all patients except for regions such as the cheeks, hands and feet. All cases had failure to thrive, microcephaly, ear dysplasia, laryngomalacia, hearing impairment, gastro-esophageal reflux disease, constipation, abnormal dentition, dermatitis/acrodermatitis enteropathica, hyperpigmentation of the skin, very low insulin-like growth factor I levels with delayed bone age, relative hypolipidemia, initial camptodactyly/joint contracture, progressive kyphoscoliosis, osteoporosis with loose joints, ventriculomegaly, and generalized organic aciduria. Other findings included inguinal hernia, hypothyroidism or persistent hyperthyrotropinemia, cryptorchidism, hip dysplasia, growth hormone deficiency, cloudy cornea with congenital glaucoma, neonatal teeth, cardiac defects, basal ganglia calcification and seizure disorder. These patients with NPS did not show hyperinsulinemia or dyslipidemia. Their karyotypes were all normal, while the chromosomal breakage test showed markedly increased breakage rates in four patients. LMNA, ERCC8, or ZMPSTE24 gene mutations could not account for the disorders in these patients. Four patients died after sepsis or aspiration pneumonia at the age of 1.1, 4, 6.2 and 7.5 years.

CONCLUSION

Increased chromosomal breakage and the presence of basal ganglia calcification after early childhood suggest that DNA repair defects are involved in the pathogenesis of this disorder. This rare disorder represents a complex of symptoms with unknown cause and pathogenesis, and more than one disease may account for the clinical variability of NPS.

Molecular ageing in progeroid syndromes: Hutchinson-Gilford progeria syndrome as a model

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder that belongs to a group of conditions called laminopathies which affect nuclear lamins. Mutations in two genes, LMNA and ZMPSTE24, have been found in patients with HGPS. The p.G608G LMNA mutation is the most commonly reported mutation. The aim of this work was to compile a comprehensive literature review of the clinical features and genetic mutations and mechanisms of this syndrome as a contribution to health care workers. This review shows the necessity of a more detailed clinical identification of Hutchinson-Gilford progeria syndrome and the need for more studies on the pharmacologic and pharmacogenomic approach to this syndrome.