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Biomedical subjects

A Gal

Publications and source records attributed to A Gal.

At least 217 records · Page 12Linked to original sources

Norrie disease as part of a complex syndrome explained by a submicroscopic deletion of the X chromosome.

A 15-year-old male patient with the typical ocular symptoms of Norrie disease is described. Additionally, he presents severe mental retardation, growth disturbances, hypogonadism, and increased susceptibility to infections. This complex syndrome is apparently segregating through three generations: four other male relatives of the patient were blind from birth and died from recurrent infections between the ages of three to 15 months. The DNA sequence of the DXS7 locus (L1.28 probe), known to be closely linked to the Norrie gene, was not found in the patient's DNA. This result suggests that the more complex clinical picture seen is the result of a deletion of the X chromosome spanning DXS7, the Norrie gene, and several neighbouring loci. A detailed clinical description of the patient is given and compared to that of similar cases.

Adolescent↗

Cholesteryl ester storage disease: a patient with massive splenomegaly and splenic abscess.

Cholesteryl ester storage disease (CESD), a rare lysosomal storage disorder characterized by functional deficiency of acid lipase activity, classically features hepatomegaly in conjunction with lipid-laden macrophages containing excessive quantities of cholesteryl esters. We present a patient whose clinical course was complicated by massive, symptomatic splenomegaly, and an unsuspected splenic abscess. Computed tomographic and magnetic resonance imaging are correlated. Histologic, electron microscopic, and biochemical features are presented. To our knowledge, this is the first report of splenic abscess in CESD.

Abscess↗

A Y/5 translocation in a 45,X male with cri du chat syndrome.

In a patient described as a 45,X male with cri du chat syndrome, combined cytogenetic and molecular methods revealed Y euchromatic material to be translocated onto the short arm of one chromosome 5, resulting in a chromosome der(5)(5qter----5p14::Yp11.31----Ypter). The translocated Y euchromatin comprised only the distal short arm including the pseudoautosomal region and the so-called deletion intervals 1 and 2. A review of 45,X males from the literature showed that; most of them carry a paternally transmitted Y/autosome translocations; resulting in various autosomal deletions. Depending on the segment concerned, the deletion led to congenital malformations.

Chromosome Banding↗

Three cases of 45,X/46,XYnf mosaicism. Molecular analysis revealed heterogeneity of the nonfluorescent Y chromosome.

Three patients with 45,X/46,XYnf mosaicism were investigated by Southern hybridization using both X- and Y-specific DNA probes. Our patients seem to be hemizygous for the X chromosomal loci tested. Single-copy and low-copy repeated Y chromosomal sequences assigned to the short arm, centromere, and euchromatin of the long arm have been detected in our patients, suggesting the Y chromosomal origin of the marker chromosome both in male and female cases studied. Densitometry of autoradiographs revealed a double dose of Yp-specific fragments of the DXYS1 locus. None of the patients tested showed either the 3.4- or the 2.1-kb Hae III male-specific repeated DNA sequences. It seems likely that the Ynf is a pseudodicentric chromosome with duplication of Yp and euchromatic Yq sequences, the Yq heterochromatin being lost. Our findings indicate structural heterogeneity of the marker chromosome and in addition provide further information on the relative position of DNA sequences detected by DNA probes 50f2, M1A, and pDP105.

Chromosome Banding↗

[Molecular genetic diagnosis in X chromosome-linked retinitis pigmentosa].

Retinitis pigmentosa (RP) is the most common hereditary dystrophic disease of the retina. About 10% of the affected families show the X-linked trait. The close link observed between the gene locus (RP2) and a polymorphic DNA marker (DXS7) on the proximal short arm of the X-chromosome permits an indirect genotype diagnosis and can be helpful in carrier detection and genetic counseling. A case is presented in which the carrier risk of a female consultant dropped from 50% a priori to less than 2% by the use of clinical findings and DNA analysis.

Adult↗

Campylobacter pyloridis gastritis I: Detection of urease as a marker of bacterial colonization and gastritis.

A method to detect the presence of Campylobacter pyloridis in dyspeptic patients is described. The test procedure involves placing a gastric pinch biopsy into a small amount of a solution containing urea and a pH indicator in the well of a microtiter tray. The method depends on the ability of C. pyloridis to hydrolyse urea and release an alkaline product (ammonia). The "microtiter biopsy urease test" is 100% specific for C. pyloridis and has a 91% sensitivity after 18 h reaction time. Seventy-five percent of positive biopsies had a reaction time of less than 1 h. The test may be used to predict the presence of antral gastritis; as well as marking the presence of the bacterium; with a positive predictive value of 96% and a negative predictive value of 73%. There was a positive correlation between the biopsy urease test results and the grades of both chronic and active antral gastritis. This test is simple and can be performed in the endoscopy clinic as the formulation of the reagent obviates the need for aseptic techniques.

Ammonia↗

A 45,X male with Y-specific DNA translocated onto chromosome 15.

A 20-year-old male patient with chromosomal constitution 45,X, testes and normal external genitalia was examined. Neither mosaicism nor a structurally aberrant Y chromosome was observed when routine cytogenetic analysis was performed on both lymphocytes and skin fibroblasts. Y chromosome-specific single-copy and repeated DNA sequences were detected in the patient's genome by means of 11 different recombinant-DNA probes of known regional assignment on the human Y chromosome. Data indicated that the short arm, the centromere, and part of the long-arm euchromatin of the Y chromosome have been retained and that the patient lacks deletion intervals 6 and 7 of Yq. High-resolution analysis of prometaphase chromosomes revealed additional euchromatic material on the short arm of one of the patient's chromosomes 15. After in situ hybridization with the Y chromosome-specific probe pDP105, a significant grain accumulation was observed distal to 15p11.2, suggesting a Y/15 chromosomal translocation. We conclude that some 45,X males originate from Y-chromosome/autosome translocations following a break in the proximal long arm of the Y chromosome.

Adult↗

Prenatal diagnosis of autosomal dominant polycystic kidney disease with a DNA probe.

A highly polymorphic DNA probe genetically linked to the locus of autosomal dominant polycystic kidney disease was used in linkage studies for prenatal diagnosis in a nine-week fetus at risk for the disease. The fetus was judged to have inherited the polycystic kidney disease mutation, and this was confirmed by microscopic examination of the fetal kidneys at necropsy.

Abortion, Therapeutic↗

A 45,X male with a Yp/18 translocation.

A patient described as a 45,X male (Forabosco et al. 1977) was examined for the presence of Y-specific DNA by using various probes detecting restriction fragments from different regions of the Y chromosome. Positive hybridization signals were obtained for Yp fragments only. In situ hybridization with two different probes, pDP31 and the pseudoautosomal probe 113F, led to a clear assignment of the Yp sequences to the short arm of one chromosome 18. Cytogenetically, the presence of all of Yp including the Y centromere on 18p could be demonstrated replacing a segment of similar size of 18p. Thus, the Y/18 translocation chromosome is dicentric structurally, but it was shown to be monocentric functionally with the no. 18 centromere active. Gene dosage studies with the probe B74 defining a sequence at 18p11.3 demonstrated a single dose of this sequence in the patient. In agreement with these observations, the patient shows clinical signs of the 18p-syndrome. It is concluded that in XO males in general, the X is of maternal origin while the maleness is due to a de novo Y/autosome translocation derived from the father. Depending on the nature of the autosomal deficiency caused by the Y/autosome translocation, the patient may have congenital malformations.

Child↗

Choroideremia-locus maps between DXS3 and DXS11 on Xq.

Choroideremia is a progressive tapetochoroidal dystrophy with X-linked transmission leading frequently to blindness in affected males. The choroideremia-locus (TCD) has recently been assigned to the long arm of the X chromosome by linkage to polymorphic DNA markers. In order to further define the location of the gene defect, two families segregating for choroideremia were examined for DNA restriction fragment length polymorphisms. A search was undertaken for linkage with cloned DNA probes from the proximal short and long arm as well as from the mid-portion of the long arm of the X chromosome. Our data suggest that the most plausible gene order on the Xq is: Xcen-DXYS1-DXS3-TCD-DXS11-Xqter.

Choroid↗

X-linked dominant hypophosphatemia is closely linked to DNA markers DXS41 and DXS43 at Xp22.

Two families with X-linked dominant hypophosphatemia (McKusick No. *30780) were investigated for linkage of the disease locus with several marker genes defined by cloned, single-copy DNA sequences derived from defined regions of the X chromosome. Close linkage was found with DNA markers DXS41 (p99-6) and DXS43 (pD2) at Xp22, suggesting a location of the HPDR gene on the distal short arm of the X chromosome.

Chromosome Mapping↗