[Show abstract][Hide abstract] ABSTRACT: CS is an autosomal recessive multisystem disorder, which is mainly characterized by neurologic and sensory impairment, cachectic dwarfism, and photosensitivity. We describe the neuroimaging features (MR imaging, ¹H-MR spectroscopy, and CT) in the various clinical subtypes of CS from a cohort of genetically and biochemically proved cases. Hypomyelination, calcifications, and brain atrophy were the main imaging features. Calcifications were typically found in the putamen and less often in the cortex and dentate nuclei. Severe progressive atrophy was seen in the supratentorial white matter, the cerebellum, the corpus callosum, and the brain stem. Patients with early-onset disease displayed more severe hypomyelination and prominent calcifications in the sulcal depth of the cerebral cortex, but atrophy was less severe in late-onset patients. On proton MR spectroscopy, lactate was detected and Cho and NAA values were decreased. These combined neuroradiologic findings can help in the differential diagnosis of CS, distinguishing it from other leukoencephalopathies and/or cerebral calcifications in childhood.
Full-text · Article · Oct 2010 · American Journal of Neuroradiology
[Show abstract][Hide abstract] ABSTRACT: Cockayne syndrome is an autosomal recessive multisystem disorder characterized principally by neurological and sensory impairment, cachectic dwarfism, and photosensitivity. This rare disease is linked to mutations in the CSB/ERCC6 and CSA/ERCC8 genes encoding proteins involved in the transcription-coupled DNA repair pathway. The clinical spectrum of Cockayne syndrome encompasses a wide range of severity from severe prenatal forms to mild and late-onset presentations. We have reviewed the 45 published mutations in CSA and CSB to date and we report 43 new mutations in these genes together with the corresponding clinical data. Among the 84 reported kindreds, 52 (62%) have mutations in the CSB gene. Many types of mutations are scattered along the whole coding sequence of both genes, but clusters of missense mutations can be recognized and highlight the role of particular motifs in the proteins. Genotype-phenotype correlation hypotheses are considered with regard to these new molecular and clinical data. Additional cases of molecular prenatal diagnosis are reported and the strategy for prenatal testing is discussed. Two web-based locus-specific databases have been created to list all identified variants and to allow the inclusion of future reports (www.umd.be/CSA/ and www.umd.be/CSB/).
[Show abstract][Hide abstract] ABSTRACT: The cerebro-oculo-facio-skeletal syndrome (COFS syndrome) is an autosomal recessive disorder which was initially described in a specific aboriginal population from Manitoba. In recent years, COFS syndrome has been linked in this original population to a defective DNA repair pathway and to a homozygous mutation in the major gene underlying Cockayne syndrome (CSB). However, most reports of suspected COFS syndrome outside this population have not been confirmed at the molecular level, leading to considerable heterogeneity within the syndrome and confusing overlaps between COFS syndrome and other eye and brain disorders.
To refine the delineation of the syndrome on genetically proven COFS cases.
We report the exhaustive clinical, cellular and molecular data of three unrelated COFS patients with mutations in the CSB gene.
All three patients present the cardinal features of COFS syndrome including extreme microcephaly, congenital cataracts, facial dysmorphism and arthrogryposis. They also exhibit a predominantly postnatal growth failure, a severe psychomotor retardation, with axial hypotonia and peripheral hypertonia and neonatal feeding difficulties. Fibroblasts from the patients show the same DNA repair defect which can be complemented by transfection of the CSB wild-type cDNA. Five new mutations in the CSB gene have been identified in these patients.
Our data indicate that COFS syndrome represents the most severe end of the Cockayne spectrum. New diagnostic criteria for COFS syndrome are proposed, based on our findings and on the few genetically proven COFS cases from the literature.
No preview · Article · Sep 2008 · Journal of Medical Genetics
[Show abstract][Hide abstract] ABSTRACT: Cockayne syndrome is an autosomal recessive neurodegenerative disorder characterized by a specific defect in the repair of UV-induced DNA lesions. Most cases of Cockayne syndrome are caused by mutations in the CSB gene but the pathophysiological mechanisms are poorly understood. We report the clinical and molecular data of two severely affected Cockayne patients with undetectable CSB protein and mRNA. Both patients showed severe growth failure, microcephaly, mental retardation, congenital cataracts, retinal pigmentary degeneration, photosensitivity and died at the ages of 6 and 8 years. UV irradiation assays demonstrated that both patients had the classical DNA repair defect. Genomic DNA sequencing of the CSB gene showed a homozygous deletion involving non-coding exon 1 and upstream regulatory sequences, but none of the coding exons. Functional complementation using a wild-type CSB expression plasmid fully corrected the DNA repair defect in transfected fibroblasts. Horibata et al recently proposed that all type of CSB mutations result in a defect in UV damage repair that is responsible for the photosensitivity observed in the syndrome, but that only truncated CSB polypeptides generated by nonsense mutations have some additional inhibitory functions in transcription or in oxidative damage repair, which are necessary to lead to the other features of the phenotype. Our patients do not fit the proposed paradigm and new hypotheses are required to account for the pathophysiology of Cockayne syndrome, at the crossroads between DNA repair and transcription.
Full-text · Article · Apr 2008 · European Journal of HumanGenetics