1/4754. Increased sister chromatid exchange in bone marrow and blood cells from Bloom's syndrome.Bone-marrow cells from a patient with Bloom's syndrome cultured for 48 h in the presence of BudR exhibited a striking increase in the number of sister chromatid exchanges (SCEs) in comparison to that in the marrow cells of a patient with treated polycythemia vera (PV). Thus, it appears that an increased incidence of SCE in Bloom's syndrome occurs in various differentiated types of cells, not just blood lymphocytes, and constitutes the syndrome's most characteristic cytogenetic feature. In contrast, the incidence of SCE was not increased in marrow cells and lymphocytes of the particular PV patient studied here, whose cells did exhibit increased numbers of chromatid and chromosome gaps and breaks, presumably as result of the patient's earlier treatment. An increased frequency of SCE was demonstrated in Bloom's syndrome lymphocytes using both a technique based on BudR incorporation and one based on labeling with tritated deoxycytidine. This observation constitutes evidence against the increase of SCE being due to an unusual reaction to BudR. By conventional cytogenetic techniques, chromosome instability, including chromatid and chromosome breaks, but no homologous chromatid interchanges were also recognized in Bloom's syndrome bone-marrow cells incubated in vitro (without BudR) for either 1.k or 16 h. This observation points to the existence of chromosome instability in vivo.- - - - - - - - - - ranking = 1keywords = chromosome (Clic here for more details about this article) |
2/4754. Phenotypic variability in the chromosome 9 ring.The syndrome associated to the 9 ring is not commonly observed. The first remark was by Kistenmacher (1970) who examined a male. Later observation of other cases has allowed the syndrome to be described, so that it can be said to be characterized by constant signs, such as microcephaly, psychomotor retardation of varying entity and facial dysmorphism corresponding to that observed in 9 p monosomy. The variability of the phenotype has to be compared with the entity of the telomeric deletion, since the clinical outlook, especially the entity of retardation, could be less serious in case of small deletions.- - - - - - - - - - ranking = 1.0165902955477keywords = chromosome, ring (Clic here for more details about this article) |
3/4754. Abnormal deposition of type VII collagen in Kindler syndrome.Kindler syndrome is an extremely rare genetic disorder with features of epidermolysis bullosa and poikiloderma congenitale. Approximately 70 cases have been documented in the past 50 years, but only a few investigations of the basement membrane components have been done on these patients. The aim of this study was to examine the components of the basement membrane zone in search of the pathobiological defect(s) responsible for the clinical findings from a female 16-year-old patient diagnosed with Kindler syndrome. This patient also suffered from advanced early-onset periodontal disease. Biopsies were taken from inflamed gingiva and noninflamed oral mucosa as part of periodontal treatment. The basement membrane zone was examined using immunofluorescence microscopy to bullous pemphigoid antigens 1 and 2, collagen types IV and VII, laminins-1 and -5, and integrins alpha3beta1 and alpha6beta4. The biopsies studied revealed blistering with trauma above the level of lamina densa based on distribution of type IV collagen and laminin-1 at the blister floor. In the noninflamed mucosa, discontinuous areas of the basement membrane zone were found. Expression of the basement membrane zone components and the integrins studied appeared otherwise normal with the exception of type VII collagen which was found in abnormal locations deep in the connective tissue stroma. Our results suggest that Kindler syndrome is associated with abnormalities in the construction of the basement membrane, especially in the expression of type VII collagen. These alterations are likely to play a role as etiological factors leading to blister formation and early onset periodontal disease.- - - - - - - - - - ranking = 0.0033180591095347keywords = ring (Clic here for more details about this article) |
4/4754. Genetic analysis of three patients with an 18p- syndrome and dystonia.Some patients with an 18p- syndrome show dystonia, and a focal dystonia gene has been mapped to chromosome 18p. The authors evaluated the extent of the deletion in three patients with an 18p- syndrome and dystonia using 14 dna markers on 18p. A common deleted area, covering the DYT7 locus, places the putative dystonia gene between the telomere of 18p and D18S1104 (49.6 cM). dystonia in these patients may be caused by haploinsufficiency of the DYT7 gene, a new dystonia gene on 18p, or may result from developmental brain anomalies.- - - - - - - - - - ranking = 0.25331805910953keywords = chromosome, ring (Clic here for more details about this article) |
5/4754. Phakomatosis pigmentovascularis: A new case with renal angiomas and some considerations about the classification.We report phakomatosis pigmentovascularis detected in a Caucasian child characterized by the presence of a nevus flammeus and nevus anemicus on the face, a telangiectatic linear nevus of the right leg, and a very extensive blue spot covering 60% of the body surface, with ocular melanosis. Multiple angiomatous lesions of the kidney are associated without alterations of the central nervous system (CNS). This association has not been reported before; it could be a further expression of the complex of developmental defects. Our case corresponds exactly to type IIb in the classification of phakomatosis pigmentovascularis proposed by Hasegawa. As this classification seems very extensive, the higher incidence of cases corresponding to the second subtype suggests that we should identify it by the term phakomatosis pigmentovascularis, while the others could be considered as only very uncommon variants.- - - - - - - - - - ranking = 0.0033180591095347keywords = ring (Clic here for more details about this article) |
6/4754. Familial cerebellar hypoplasia and pancytopenia without chromosomal breakages.Two siblings manifested a neuro-haematologic syndrome characterised by low birth weight, failure to thrive, chronic persistent tongue ulceration, severe truncal ataxia and pancytopenia without either telangiectasia or chromosomal instability. One sibling died from sepsis and the cerebellum demonstrated reduced cellularity of the molecular and granular layers with relative preservation of purkinje cells and minimal gliosis. A surviving sibling has shown haematologic progression to a myelodysplastic disorder. There was no evidence of any chromosomal instability following exposure of fibroblasts and lymphocytes to irradiation. monosomy-7 was not present in the surviving sibling. We suspect that these two patients represent another example of the rare Hoyeraal-Hreidarsson syndrome and we are currently engaged in very close monitoring of the surviving sibling for evidence of any karyotypic abnormality.- - - - - - - - - - ranking = 0.0033180591095347keywords = ring (Clic here for more details about this article) |
7/4754. patients with CHARGE association: a model to study saccular function in the human.The term CHARGE association refers to a combination of congenital malformations, the mnemonic CHARGE designating the most frequently occurring anomalies in the constellation. "C" indicates coloboma of the retina, "H" heart defects, "A" choanal atresia, "R" retarded growth and/or central nervous system anomalies, "G" genital hypoplasia, and "E" ear anomalies and/or deafness. The inner ear anomaly consists of a specific form of labyrinthine dysplasia that includes Mondini dysplasia of the pars inferior (cochlea and saccule) and complete absence of the pars superior (utricle and semicircular canals). We observed the development of a child with CHARGE association up to the age of 10 years. There was complete absence of nystagmic response to bithermal caloric and rotatory pendular stimuli. A nystagmic reaction was elicited by the off-vertical axis rotation test, indicating stimulation of the saccular macula, the sole remaining vestibular sense organ in this dysplasia. This reaffirms that the saccule is a vestibular organ, even though it is located in the pars inferior. In spite of the severe bilateral vestibular deficit and coloboma of the retina, the child was able to walk at the age of 2 years. The delay in the development of walking was not due to central nervous system anomalies, as suggested by the "R" of the acronym CHARGE, but rather, to the severe sensorineural visual and vestibular deficits.- - - - - - - - - - ranking = 0.0033180591095347keywords = ring (Clic here for more details about this article) |
8/4754. Prenatal and postnatal management of hyperprostaglandin E syndrome after genetic diagnosis from amniocytes.OBJECTIVE: To describe prenatal genetic diagnosis in hyperprostaglandin E syndrome (HPS) and the effect of indomethacin therapy on the course of the disease before birth and in the neonatal period. methods: Mutational analysis of the ROMK channel gene (KCNJ1) from amniocytes by single-strand conformational analysis and direct sequencing. review of the clinical and laboratory findings during pregnancy and the neonatal period in two siblings affected with HPS. RESULTS: Compound heterozygosity of the fetus in KCNJ1 (D74Y/P110L) confirmed the clinical diagnosis of HPS at 26 weeks of gestation. indomethacin therapy from 26 to 31 weeks prevented further progression of polyhydramnios without major side effects. In contrast to the elder brother, who had been diagnosed at the age of 2 months, the neonatal course was uncomplicated. Hypovolemic renal failure after excessive renal loss of salt and water could be prevented and severe nephrocalcinosis did not occur. CONCLUSIONS: Genetic diagnosis of HPS and subsequent prenatal indomethacin therapy seems to have a beneficial effect on the natural course of HPS, especially progression of polyhydramnios; therefore, extreme prematurity could be prevented. Also, postnatally the early diagnosis allows the effective water and electrolyte substitution before severe volume depletion.- - - - - - - - - - ranking = 0.0033180591095347keywords = ring (Clic here for more details about this article) |
9/4754. ataxia, ocular telangiectasia, chromosome instability, and Langerhans cell histiocytosis in a patient with an unknown breakage syndrome.An 8 year old boy who had Langerhans cell histiocytosis when he was 15 months old showed psychomotor regression from the age of 2 years. microcephaly, severe growth deficiency, and ocular telangiectasia were also evident. Magnetic nuclear resonance imaging showed cerebellar atrophy. Alphafetoprotein was increased. Chromosome instability after x irradiation and rearrangements involving chromosome 7 were found. Molecular study failed to show mutations involving the ataxia-telangiectasia gene. This patient has a clinical picture which is difficult to relate to a known breakage syndrome. Also, the relationship between the clinical phenotype and histiocytosis is unclear.- - - - - - - - - - ranking = 1.25keywords = chromosome (Clic here for more details about this article) |
10/4754. monosomy 18q syndrome and atypical rett syndrome in a girl with an interstitial deletion (18)(q21.1q22.3).We describe a 6 1/2-year-old girl with an interstitial deletion of chromosome arm 18q (18q21.1q22.3). Her clinical manifestations are a combination of those found in monosomy 18q syndrome and those of rett syndrome. cytogenetic analysis demonstrated a deletion of the long arm of chromosome 18, defined by molecular analysis with polymorphic markers as a de novo interstitial deletion, paternally derived. The findings typical of the 18q- syndrome included mental retardation, midface hypoplasia, and hypoplasia of labia majora, and those typical of rett syndrome were severe mental retardation, autistic behavior, inappropriate hand-washing movements, epilepsy, attacks of sighing and hyperventilation, and progressive scoliosis since the age of 5 years. She did not have microcephaly, and the mental delay was obvious from an early age without a period of normal development, which makes the diagnosis of rett syndrome atypical. Previously, a girl with mosaicism for a monosomy 18q associated with rett syndrome has been described. That girl had a terminal deletion of chromosome 18q, which seems to coincide in part with that in the present girl. It is possible that genes in the distal region of 18q are involved in the etiology of rett syndrome.- - - - - - - - - - ranking = 0.75keywords = chromosome (Clic here for more details about this article) |
| | Next -> |