1/17. Partial monosomy and partial trisomy 18 in two offspring of carrier of pericentric inversion of chromosome 18.A pericentric inversion of chromosome 18 is described in the mother of a patient with clinical diagnosis of 18q--syndrome. The propositus' chromosome complement includes the recombinant 18 with deficiency of the distal one-third of the long arm and duplication of the terminal segment of the short arm. The propositus' sister carrier the recombinant 18 with a duplication of the distal one-third of the long arm and a deficiency of the terminal segment of the short arm. The relative length of the inverted segment represents about 60% of the total chromosome 18 length. The probability of recombinant formation following the occurrence of a chiasma within the inverted segment is predicted to be high.- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
2/17. Early prenatal diagnosis of the ICF syndrome.The ICF syndrome (immunodeficiency, (para)centromeric instability and facial abnormalities) is a rare autosomal recessive disorder with characteristic cytogenetic aberrations of chromosomes 1, 9 and 16 in lymphocytes. Previously, only one case has been diagnosed prenatally in the second trimester of pregnancy by fetal blood sampling. We report the first early prenatal exclusion of the ICF syndrome by chorionic villous sampling (CVS) and linkage analysis in a family with a previous affected child. The fetus was heterozygous for marker D20S850 closely linked to the ICF locus. The family was counselled of a probability of over 90% that the fetus would be unaffected. Postnatal chromosome analysis on peripheral blood was normal and thus confirmed the prenatal diagnosis.- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
3/17. Monitoring minimal residual disease in patients with MLL-AF6 fusion transcript-positive acute myeloid leukemia following allogeneic bone marrow transplantation.Acute myeloid leukemia (AML) patients with chromosome 11q23 abnormalities or MLL rearrangements have a poor prognosis when treated with conventional chemotherapy. However, the efficacy of allogeneic bone marrow transplantation (BMT) for this type of leukemia is not yet clear. We describe 2 MLL-AF6 fusion transcript-positive AML patients treated with allogeneic BMT who were monitored for minimal residual disease (MRD) by reverse transcriptase polymerase chain reaction. Although long survival or cure of this type of AML is rarely reported, 1 patient had durable remissions. Fusion transcripts disappeared in 1 patient but not in the other, even after the graft-versus-host disease effect was increased by the discontinuation of immmunosuppressive therapy. This is the first report of MRD and the probability of graft-versus-leukemia effects following BMT in AML patients who are MLL-AF6 fusion transcript positive.- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
4/17. Congenital leukaemia: the Dutch experience and review of the literature.We reviewed Dutch patients and those described in the literature with congenital leukaemia in the past 25 years, with the intention to obtain an overview of the characteristics of this rare disease. Among the 117 patients reviewed, acute myeloid leukaemia (AML) was more frequent (64%) than acute lymphoblastic leukaemia (ALL, 21%). Most patients had a high leukaemic cell load with hepatosplenomegaly, leukaemia cutis and hyperleucocytosis. Cytogenetic abnormalities were found in the majority of the patients tested (72%); 11q23 abnormalities were found in less than half of them (42%). The probability of overall survival at 24 months was only 23%. When congenital AML and ALL were compared, clinical characteristics and overall survival were not significantly different. However, in patients at risk, the probability of event-free survival (EFS) and disease-free survival (DFS) were significantly higher in AML than in ALL, 43% versus 13% and 68% versus 0% respectively. Among the congenital AML cases, six spontaneous remissions have been described. In conclusion, the clinical characteristics of congenital leukaemia differ from those of leukaemia in older children and prognosis is generally poor. Once complete remission is achieved, patients with AML fare better than those with ALL. Chemotherapy for congenital leukaemia needs improvement to increase the sustained remission rate.- - - - - - - - - - ranking = 2keywords = probability (Clic here for more details about this article) |
5/17. Sezary's syndrome: a cytogenetic, cytophotometric and autoradiographic study.Cytophotometric, cytogenetic, and autoradiographic studies were performed in cells of three patients suffering from clinically diagnosed Sezary's syndrome with erythroderma and the presence of abnormal lymphoid cells in the peripheral blood, skin, bone marrow and lymph-nodes. Feulgen DNA cytophotometry of cells in the peripheral blood and skin lesions showed marked aneuploidy and tetraploidy. Multiple translocations were identified with a G-banding technique. The chromosomal abnormalities varied widely between the patients, but C and D group chromosomes were more frequently involved than others. All breakpoints of the translocations were localised in the centromeric region. autoradiography of blood and skin samples revealed many labelled cells in the skin and a lower number in the blood, indicating cell proliferation in the skin. It is concluded that the pathological cells occurring in the sezary syndrome are abnormal lymphoid cells with a tendency to proliferate in the dermis. The variability observed between and in the patients is in all probability due to a difference in the degree of dedifferentiation.- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
6/17. Partial trisomy 8q. Two case reports with maternal translocation and inverted insertion: phenotype analyses and reflections on the risk.Partial trisomy 8qter-->q23 or q24.1 has been reported in 15 literature cases. We add two further case reports here. Patient 1 inherited the derivative (2) of a balanced maternal reciprocal translocation t(2;8)(qter;q2300) after 2:2 disjunction and adjacent-1 segregation, and is trisomic for the segment 8qter-->q2300. Patient 2 inherited a recombinant (8) of a balanced maternal inverted insertion inv ins(8)(q1300;q2300q24.2) and is trisomic for the segment 8q24.2-->q2300. The phenotype of both patients is described and compared to the spectrum of symptoms established from the 15 literature cases. This spectrum contains all features observed with a frequency of > = 50%. Patient 1 had 35% of the features of this spectrum; Patient 2 had 47%. The intrauterine survival probability of unbalanced offspring is assumed to be the same in both cases, as nearly the same segments are trisomic. The pedigrees indicate that the inversion carrier may have a reduced production probability of unbalanced gametes and therefore a reduced risk compared to the translocation carrier.- - - - - - - - - - ranking = 2keywords = probability (Clic here for more details about this article) |
7/17. Intrachromosomal triplication 12p11.22-p12.3 and gonadal mosaicism of partial tetrasomy 12p.Cases of tetrasomy 12p and trisomy 12p are known to be associated with specific phenotypic abnormalities well described in the literature. Here, we report on the unusual case of a partial tetrasomy 12p found in an affected patient and in a mosaic constellation in the patient's mother, who showed no phenotypic abnormality. The index patient was a 16-year-old boy with clinical features similar to the "trisomy 12p syndrome" including mental retardation, macrocephaly, a short nose with anteverted nostrils, and a broad protruding lower lip. G-banding analysis and fluorescence in situ hybridization (FISH) experiments using locus specific YAC dna probes revealed a derivative chromosome 12 with a partial triplication of the short arm with an inverted copy, flanked by two direct copies. Chromosome analyses in parental lymphocytes showed a chromosomal mosaicism in the phenotypically normal mother, with 12% cells exhibiting the same partial tetrasomy 12p as detected in her son. The allelic pattern of short tandem repeats (STR) in the mother's blood DNA showed that a chimerism can be excluded with high probability. To our knowledge, this is the first report of intrachromosomal triplication on chromosome 12, as well as partial tetrasomy 12p mosaicism. Moreover, as a consequence of the chromosomal aberration in the son it can be concluded that a gonadal mosaicism is present in the mother.- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
8/17. family with 22-derived marker chromosome and late-onset dementia of the Alzheimer type: I. Application of a new model for estimation of the risk of disease associated with the marker.We have identified 2 sisters with probable dementia of the Alzheimer type who have an unusual 22-derived marker chromosome with a greatly elongated short arm containing 2 well-separated nucleolus organizer regions. A marker chromosome similar in appearance is uncommon in the general population. Eleven of 24 of their biological relatives were also found to have the marker. The known pedigree of this family encompasses 6 generations in 2 of which there is evidence of 10 cases of dementia of the Alzheimer type. The average age-at-onset of dementia is 65.8 /- 5.5 years; the average age-at-death among those apparently affected is 74.9 /- 8.3 years. A new model for the estimation of risk was applied to the family data. persons in this family with the marker were found to be 4 times more likely to develop dementia than those without the marker, the 95% confidence interval for this risk being 1-50. The probability that the association of dementia and the marker is due to chance alone is .05 (1 in 20).- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
9/17. Cerebral haemorrhage and berry aneurysm: evidence from a family for a pattern of autosomal dominant inheritance.Although families with several members suffering a cerebral haemorrhage have been reported previously, a family history of this stroke sub-type has not yet been firmly established as a risk factor for the disease. A family in whom cerebral haemorrhage has been clearly documented in five members, spanning three generations, is reported. In three a berry aneurysm was detected. There was no evidence of hypertension among any of the five cases. A sixth member of the family probably died of a cerebral haemorrhage but no necropsy was performed. By using established incidence rates for cerebral haemorrhage in the population, the probability of five such unrelated events arising in any family of similar size and longevity was calculated to be 4.9 x 10(-10). This family strengthens the case that an underlying genetic susceptibility does exist for a proportion of patients who have a cerebral haemorrhage. This susceptibility appears to be consequent upon berry aneurysm formation. The distribution of cases within this family is consistent with an autosomal dominant pattern of inheritance.- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
10/17. Monozygotic twins with trisomy 18: a report of discordant phenotype.The predicted incidence of liveborn monozygotic trisomy 18 twins is one per million births. The first case of liveborn monozygotic trisomy 18 twins was reported in 1989 and we report a second case in which striking phenotypic discordance existed. The probability of monozygotic trisomy 18 twinning and the mechanisms for phenotypic discordance in trisomic twins is discussed.- - - - - - - - - - ranking = 1keywords = probability (Clic here for more details about this article) |
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