Follow-up study of Wiedemann-Rautenstrauch syndrome: Long-term survival and comparison with Rautenstrauch's patient “G”

WIEDEMANN–RAUTENSTRAUCH SYNDROME: CASE REPORT

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Nucleolar disruption, activation of P53 and premature senescence in POLR3A-mutated Wiedemann-Rautenstrauch syndrome fibroblasts

Recently, mutations in the RNA polymerase III subunit A (POLR3A) have been described as the cause of the neonatal progeria or Wiedemann-Rautenstrauch syndrome (WRS). POLR3A has important roles in transcription regulation of small RNAs, including tRNA, 5S rRNA, and 7SK rRNA. We aim to describe the cellular and molecular features of WRS fibroblasts. Cultures of primary fibroblasts from one WRS patient [monoallelic POLR3A variant c.3772_3773delCT (p.Leu1258Glyfs*12)] and one control patient were cultured in vitro. The mutation caused a decrease in the expression of wildtype POLR3A mRNA and POLR3A protein and a sharp increase in mutant protein expression. In addition, there was an increase in the nuclear localization of the mutant protein. These changes were associated with an increase in the number and area of nucleoli and to a high increase in the expression of pP53 and pH2AX. All these changes were associated with premature senescence. The present observations add to our understanding of the differences between Hutchinson-Gilford progeria syndrome and WRS and opens new alternatives to study cell senesce and human aging.

Anesthesia in an Aging Infant: Neonatal Progeroid Syndrome

Neonatal progeroid syndrome is a unique condition wherein features of aging are apparent in a newborn at birth. It is a very rare genetic disorder. The first case in India was reported in December 2011. The anesthetic management of any infant with this condition could not be found in the medical literature. Independently described by Rautenstrauch and Wiedemann, neonatal progeroid syndrome poses significant challenges to the anesthesiologist for a variety of anatomic and physiologic reasons. Coronary and cerebrovascular atherosclerosis pose significant concerns in such children. Here, we present the successful anesthetic management of a 6-month-old male infant with neonatal progeroid syndrome operated on for bilateral inguinoscrotal swellings.

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.

Body fat distribution and metabolic variables in patients with neonatal progeroid syndrome

Neonatal progeroid syndrome (NPS), also known as Wiedemann-Rautenstrauch Syndrome, is a rare autosomal recessive disorder characterized by accelerated aging and lipodystrophy from birth. Affected children have extreme intrauterine growth retardation, poor postnatal weight gain, and characteristic facial dysmorphic features such as a triangular shape, pinched nose, pseudohydrocephalus with wide fontanelles and prominent subcutaneous (sc) veins. Generalized loss of sc fat has been reported as a cardinal feature; however, the pattern of fat loss and its association with insulin resistance and its metabolic complications have not been systematically studied. The aim of the current study was to examine body fat distribution and body composition in two girls with NPS using anthropometric measures, whole-body magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DEXA), and to assess metabolic complications such as hyperinsulinemia and dyslipidemia. Both the girls (aged 17 years and 10 years, respectively) had generalized paucity of sc fat on physical examination. However, measurements of skin-fold thickness revealed that sc fat was decreased over the extremities, but preserved over the chest and abdomen. MRI studies confirmed the presence of normal amounts of sc truncal fat, and marked loss of fat from the face and distal extremities. Striking fat loss was also noted in the paravertebral and lateral gluteal regions. Interestingly, body composition analysis with DEXA scan revealed a marked reduction in both the fat and lean tissue mass. Fasting glucose, lipids and insulin levels were not elevated. We conclude that patients with NPS do not have generalized lipodystrophy as previously reported, but fat loss is confined to the face, distal extremities, and possibly the paravertebral and lateral gluteal regions. Metabolic abnormalities related to insulin resistance are also uncommon in this condition.

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

The Wiedemann-Rautenstrauch syndrome (WRS) characterises a premature aging syndrome in which several features of human aging are apparent at birth therefore allowing their grouping as a neonatal progeroid condition. This differentiates WRS from other progeroid entities such as Hutchinson-Gilford progeria syndrome (HGPS) in which characteristics of premature aging become apparent some time after birth. The etiology of WRS remains unknown. Some studies have observed an autosomal recessive mode of inheritance. Several studies analysing telomere length and lamin A gene have not revealed any alterations. However, mutations in LMNA have been reported in several other atypical progeroid syndromes. Based on these observations, several hypothesis could be withdrawn concerning the etiology of WRS. The study of genes associated with lamin A metabolism, such as Zmpste24, and the metabolic pathways associated with insulin, such as protein kinase B or AKT, are of particular interest. We believe that WRS characteristics indicate that discovery of the gene and the metabolic pathway associated with this syndrome will most likely lead to new knowledge about the physiopathology of human aging.