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Biomedical subjects

A Gal

Publications and source records attributed to A Gal.

At least 199 records · Page 11Linked to original sources
PubMed1990

Localization of the X-linked ocular albinism gene (OA1) between DXS278/DXS237 and DXS143/DXS16 by linkage analysis.

Linkage analysis was performed in six families segregating for X-linked ocular albinism of the Nettleship-Falls type using four polymorphic DNA markers from the distal Xp. Linkage was found between the disease locus (OA1) and the loci DXS237 (theta max = 0.06, Zmax = 2.82), DXS278 (theta max = 0.03, Zmax = 5.27) and DXS16 (theta max = 0.10, Zmax = 2.33). The analysis of multiple informative meioses suggests that OA1 maps between DXS278/DXS237 and DXS143/DXS16. Multipoint linkage analysis slightly favours the order DXS278/DXS237-OA1-DXS16. These data refine the genetic localization of OA1 and may be useful for carrier detection in X-linked ocular albinism by DNA analysis.

Albinism, Ocular↗
PubMed1990

Transabdominal placental biopsy in the second and third trimesters of pregnancy: what is the risk of maternal contamination in DNA diagnosis?

We investigated the risk of maternal contamination in antenatal DNA diagnosis after second- and third-trimester transabdominal placental biopsy. For this purpose, we compared the restriction fragment length polymorphism (RFLP) patterns of 11 chorionic villus DNA samples after late chorionic villus sampling (CVS) with those of the corresponding maternal DNA. Ten of 11 aspirated tissue samples were not separated from maternal contamination before DNA extraction. All 11 mother-embryo pairs were informative for analysis of maternal contamination, ie, the mother showed one RFLP allele not present in the embryo. In none of the 11 cases did the fetal DNA show maternal contamination after molecular hybridization, although ten samples were contaminated with maternal tissue macroscopically and microscopically. Despite some maternal tissue admixture, the risk of contamination seems to be lower in the second- and third-trimester CVS than in first-trimester CVS, based on previous reports and our own experiences. This is most likely due to the anatomically closer contact of villi and decidua in the first trimester of pregnancy.

Alleles↗
PubMed1989

Gene of X-chromosomal congenital stationary night blindness is closely linked to DXS7 on Xp.

Congenital stationary night blindness is characterized disturbed or absent night vision that is always present at or shortly after birth and nonprogressive. The X-linked form of the disease (CSNBX; McKusick catalog no. 31050) differs from the autosomal types in that the former is frequently associated with myopia. X-chromosome-specific polymorphic DNA markers were used to carry out linkage analysis in three European families segregating for CSNBX. Close linkage without recombination was found between the disease locus and the anonymous locus DXS7, mapped to Xp11.3, assigning the mutation to the proximal short arm of the X chromosome. Linkage data obtained with markers flanking DXS7 provided further support for this localization of the gene locus. Thus, in addition to retinitis pigmentosa and Norrie disease, CSNBX represents the third well-known hereditary eye disease the locus of which is mapped on the proximal Xp and closely linked to DXS7.

Chromosome Mapping↗
PubMed1989

Gene diagnosis in X-linked ichthyosis.

Three families segregating for X-linked ichthyosis (XLI) were analysed using the full-length STS cDNA probe and an anonymous polymorphic DNA sequence closely linked to the STS gene. In patients from two of the families, submicroscopic chromosomal deletions could be detected using both the STS and the GMGX9 (DXS237 locus) probes. Patients in the third family showed the same hybridization pattern as healthy males following molecular hybridization with either of the probes. The results of DNA analysis (indirect genotype diagnosis) agree well with those based on the arysulfatase C/beta-gal determination and prove the reliability of the biochemical test. Both methods are discussed for carrier detection, prenatal diagnosis, and genetic counseling.

Arylsulfatases↗
PubMed1989

Human monoamine oxidase A and B genes map to Xp 11.23 and are deleted in a patient with Norrie disease.

Monoamine oxidase A and B (MAO A and B) are the central enzymes that catalyze oxidative deamination of biogenic amines throughout the body. The regional locations of genes encoding MAO A and B on the X chromosome were determined by using full-length cDNA clones for human MAO A and B, respectively. Using somatic cell hybrids, in situ hybridization, and field-inversion gel electrophoresis as well as deletion mapping in a patient with Norrie disease, we concluded that these two genes are close to each other and to the DXS7 locus (Xp 11.3).

Animals↗
PubMed1989

Childhood manifestation of autosomal dominant polycystic kidney disease: no evidence for genetic heterogeneity.

Autosomal dominant polycystic kidney disease (ADPKD) usually becomes symptomatic between the third and fifth decades. We studied ten families segregating for ADPKD in which children were observed with typical manifestations of the disease at birth or in early childhood. In these families, linkage analysis was carried out with a cloned DNA sequence from the alpha-globin locus known to be closely linked to the disease gene in adult onset ADPKD. In the families studied here, close linkage (theta max = 0.09 at zmax = 2.32) was also observed between the marker and disease loci. These results provide no evidence for genetic heterogeneity of ADPKD in families with early and adult onset.

Child↗
PubMed1989

[Norrie syndrome: identification of carriers by segregation analysis with flanking DNA markers].

Norrie disease is an X-linked recessive disorder. Affected males present with congenital blindness. Additionally, hearing loss and psychotic behavior may occur at any time. Since carriers are clinically healthy, they can only be identified by genetic means. Daughters of carriers or sisters of affected males have an à priori 50% risk of being carriers themselves. Close linkage has been found between the Norrie disease locus (NDP) and the DNA locus DXS7 mapped to Xp11.3. For genetic counselling, this linkage relationship allows carriers of the disease to be identified in informative families. We describe a large pedigree with Norrie disease. Segregation analysis was carried out with DXS7 and a second flanking marker, DXS255, both linked to NDP. In this way, three females at risk were identified who had a high probability of being carriers for Norrie disease.

Adult↗
PubMed1988

Albumin and alpha-fetoprotein gene expression in various nonhepatic rat tissues.

Albumin and alpha-fetoprotein (AFP), two major serum proteins, are synthesized predominantly in the liver and yolk sac of mammals. In the present paper we report on the developmental expression of the corresponding genes in nonhepatic rat tissues. Significant quantities of mature albumin and AFP mRNAs were revealed in kidney, pancreas, heart, and lung of fetal and/or newborn rats using dot blot and Northern blot assays. Very low levels of these mRNA sequences were also detected in adult kidney and pancreas using sensitive RNA-cDNA solution hybridization assays. In situ hybridization analysis revealed that the albumin and AFP gene transcripts are present in the tubular cells of the 20-day-old fetal kidney. In order to elucidate further the mechanisms governing this expression, we studied the chromatin structure and methylation pattern in the 5'-end of these two genes. A faint band, corresponding to a specific DNase I-hypersensitive site upstream from the albumin gene, was detected in the fetal and neonatal kidney nuclei but not in adult kidney. For both genes, a site CG, demethylation of which is correlated with expression in liver and hepatoma cell lines, is highly methylated in fetal kidney even though AFP and albumin genes are expressed. Taken together, these results show the presence of a cell population in the rat kidney that actively transcribes both the albumin and AFP genes. The expression of these genes may be mediated by mechanisms differing in at least some steps from those exerted in the liver.

Animals↗
PubMed1988

Role of the cytochrome b6.f complex in the redox-controlled activity of Acetabularia thylakoid protein kinase.

The regulation of the protein kinase activity responsible for the phosphorylation of the light-harvesting complex of photosystem II (LHCII) 27-kDa polypeptide involved in the State I-State II transitions in Acetabularia thylakoids was investigated. The LHCII kinase of isolated thylakoids retains its activity in absence of light-driven electron flow or reductants added in the dark. However, the kinase is reversibly inactivated by addition of oxidants in vitro or by far red (710 nm) light in vivo. Inhibitors of the quinol oxidase site of the cytochrome b6.f complex inactivate the LHCII kinase in the dark, and also in the light, or in presence of duroquinol when the plastoquinone pool is reduced. Inhibitors of the quinone reductase site of the b6.f complex have practically no effect in the dark and stimulate the kinase activity in the light. Based on these data and on our previous report, showing specific loss of LHCII kinase activity in a Lemna mutant lacking the cytochrome b6.f complex (Gal, A., Shahak, Y., Schuster, G., and Ohad, I. (1987) FEBS Lett. 221, 205-210), we propose that the activity of the LHCII kinase is regulated by the redox state of a cytochrome b6.f complex component(s) which responds to the balance of electron flow from photosystem II via the plastoquinone pool to photosystem I.

Acetabularia↗
PubMed1988

Prenatal exclusion of Norrie disease with flanking DNA markers.

Three polymorphic DNA markers linked to the locus of Norrie disease were used for indirect genotype analysis in a ten-wk-old fetus at risk for the disease. When haplotypes of the family members and the estimated recombination frequency between Norrie gene and each of the DNA marker loci DXS7, DXS84, and DXS146 were taken into account, the risk that the fetus had inherited the mutation was about 1%.

Adult↗
PubMed1988

Linkage analysis in X-linked ichthyosis (steroid sulfatase deficiency).

Linkage analysis has been carried out in nine unrelated families segregating for X-linked ichthyosis (steroid sulfatase deficiency) using seven polymorphic DNA markers from the distal Xp. Close linkage was found between the disease locus and the loci DXS16, DXS89, and DXS143. In all families except one, Southern hybridization with the human steroid sulfatase cDNA and GMGX9 probes showed a deletion of corresponding loci in affected males. Three patients belonging to the same family had no evident deletion with either of the two above-mentioned probes. None of the other six DNA loci included in the linkage analysis were found to be deleted.

Arylsulfatases↗
PubMed1988

Two different genes for X-linked retinitis pigmentosa.

Linkage analysis was carried out in three large multigenerational kindreds with X-linked retinitis pigmentosa using DNA markers on Xp. About 10% recombination has been found between the retinitis pigmentosa locus (RP2) and the marker locus DXS7, assigned to band Xp11.3, which was reported earlier to be closely linked to RP2 in several independent families. In the kindreds described in this paper, however, RP2 shows close linkage and no recombination with the marker loci OTC and DXS148, both assigned to Xp21, indicating that, contrary to previous linkage studies, there is evidence of an RP locus distal to DXS7. This suggests that X-linked retinitis pigmentosa is genetically heterogeneous, i.e., caused by mutations at different loci.

Female↗