1/4. Trichothiodystrophy, a human dna repair disorder with heterogeneity in the cellular response to ultraviolet light.Trichothiodystrophy (TTD) is an autosomal recessive disorder characterized by brittle hair with reduced sulfur content, ichthyosis, peculiar face, and mental and physical retardation. Some patients are photosensitive. A previous study by Stefanini et al. (Hum. Genet., 74: 107-112, 1986) showed that cells from four photosensitive patients with TTD had a molecular defect in dna repair, which was not complemented by cells from xeroderma pigmentosum, complementation group D. In a detailed molecular and cellular study of the effects of UV light on cells cultured from three further TTD patients who did not exhibit photosensitivity we have found an array of different responses. In cells from the first patient, survival, excision repair, and DNA and rna synthesis following UV irradiation were all normal, whereas in cells from the second patient all these responses were similar to those of excision-defective xeroderma pigmentosum (group D) cells. With the third patient, cell survival measured by colony-forming ability was normal following UV irradiation, even though repair synthesis was only 50% of normal and rna synthesis was severely reduced. The excision-repair defect in these cells was not complemented by other TTD cell strains. These cellular characteristics of patient 3 have not been described previously for any other cell line. The normal survival may be attributed to the finding that the deficiency in excision-repair is confined to early times after irradiation. Our results pose a number of questions about the relationship between the molecular defect in dna repair and the clinical symptoms of xeroderma pigmentosum and TTD.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
2/4. cockayne syndrome with early onset of manifestations.The cockayne syndrome is an autosomal recessive syndrome of growth failure and characteristic physical and pathological changes. Typically the disorder becomes manifest in the second year of life; growth and development are normal during the first year. We report presumably monozygotic twins with otherwise classic cockayne syndrome but with a prenatal onset. Several previously described cases seem to represent a similar form of cockayne syndrome with early onset of growth failure and development delay.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
3/4. Cockayne's syndrome: dental findings and management.A case report is presented to familiarize the dental practitioners with Cockayne's Syndrome (CS), a rare autosomal recessive premature aging syndrome. Significant physical and dental findings contributed to a most challenging case for the dentist and anesthesiologist.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
4/4. Nondetectable cone and rod electroretinographic responses in a patient with cockayne syndrome.A 10-year-old girl complained or poor vision in both eyes. The patient showed progeria, physical and mental retardation, sensorineural hearing loss, cutaneous photosensitivity, hyperopia, poor pupillary dilation, exotropia, salt-and-pepper fundi, nondetectable cone and rod electroretinographic (ERG) responses, cerebral atrophy on computed tomography, and demyelination of periventricular white matter on magnetic resonance imaging. We believe that nondetectable cone and rod ERG responses in cockayne syndrome, as demonstrated in our patient, may be uncommon.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |