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M Anvret

Publications and source records attributed to M Anvret.

At least 127 records · Page 7Linked to original sources

Genetic mapping of loci for X-linked retinitis pigmentosa.

Linkage analysis was performed in three Swedish families segregating for X-linked retinitis pigmentosa (XLRP), using five polymorphic DNA markers assigned to Xp. Individual recombination events were analyzed and two- and five-point linkage analysis was undertaken. In one family, a XLRP locus was mapped to the same position as OTC corresponding to RP3. In two families, a disease locus linked to OTC was excluded. In one family, recombination events indicate a locus for XLRP outside the interval (DXS84-OTC-DXS255-DXS14), most likely on the centromeric side of DXS14.

Chromosome Mapping↗

A human XY female with a frame shift mutation in the candidate testis-determining gene SRY.

The primary decision about male or female sexual development of the human embryo depends on the presence of the Y chromosome, more specifically on a gene on the Y chromosome encoding a testis-determining factor, TDF. The human sex-determining region has been delimited to a 35-kilobase interval near the Y pseudoautosomal boundary. In this region there is a candidate gene for TDF, termed SRY, which is conserved and specific to the Y chromosome in all mammals tested. The corresponding gene from the mouse Y chromosome is deleted in a line of XY female mutant mice, and is expressed at the expected stage during male gonadal development. We have now identified a mutation in SRY in one out of 12 sex-inversed XY females with gonadal dysgenesis who do not lack large segments of the short arm of the Y chromosome. The four-nucleotide deletion occurs in a sequence of SRY encoding a conserved DNA-binding motif and results in a frame shift presumably leading to a non-functional protein. The mutation occurred de novo, because the father of the sporadic XY female that bears it has the normal sequence at the corresponding position. These results provide strong evidence for SRY being TDF.

Amino Acid Sequence↗

Segregation analysis of the X-chromosome in a family with Rett syndrome in two generations.

We report on the first family in which Rett syndrome (RTS) appeared in two consecutive generations. The index case is a 12-year-old girl (classical RTS); her maternal aunt, age 44 years, has mild RTS. Clinically, the family illustrates the wide phenotypic variability between cases, particularly in severity of neurological manifestations. We have analyzed the short arm of the X-chromosome of the family with gene technology. This did not uncover any genetic marker for diagnosis, but it did suggest how the syndrome might have segregated in the family. A cytogenetic analysis gave no information about chromosome abnormalities.

Adult↗

Haplotyping of the human porphobilinogen deaminase gene in acute intermittent porphyria by polymerase chain reaction.

Acute intermittent porphyria (AIP) is due to a defect in porphobilinogen deaminase (PBGD, E.C. 4.1.3.8) inherited as an autosomal dominant trait. Presymptomatic carrier detection is important in order to avoid exposure to factors inducing severe clinical symptoms. Carriers and noncarriers of the AIP gene can be distinguished by linkage analysis using three intragenic RFLPs in AIP families. In the present study, the polymerase chain reaction (PCR) was used to amplify 3.3-kb genomic sequences covering three polymorphic sites. Haplotypes were identified after cleavage of amplified products with three restriction enzymes, showing that the technique can be successfully used for linkage analysis in AIP families.

Acute Disease↗

A normal male with an inherited deletion of one exon within the DMD gene.

We describe two brothers with identical inherited deletions of one single exon within the middle of the DMD gene; one brother has Becker muscular dystrophy diagnosed at 11 years of age, whereas the older brother is normal at 18. These results have implications for genetic counselling and prenatal diagnosis in families with Becker muscular dystrophy.

Adolescent↗

A new polymorphic probe which defines the region of chromosome 19 containing the myotonic dystrophy locus.

The region of human chromosome 19 which includes the myotonic dystrophy locus (DM) has recently been redefined by the tight linkage between it and the gene for muscle-specific creatine kinase (CKMM), which lies just proximal to DM. Utilizing human/hamster hybrid cell lines containing defined breakpoints within this region, we have assigned a number of new probes close to DM. Two of these probes, p134B and p134C, were isolated from a single cosmid clone (D19S51) and detect the same BglI RFLP; p134C detects an additional RFLP with the enzyme PstI. Analysis of these probes in the Centre d'Etude du Polymorphisme Humain families demonstrates tight linkage with a number of markers known to be proximal to DM. A two-point lod score of 6.34 at theta = .025 demonstrates the linkage of this probe to DM. Analysis of a DM individual previously shown to be recombinant for other tightly linked markers indicates that p134C is distal to DM. This result indicates that both the new probe and the existing group of proximal probes including CKMM and ERCC1 probably flank DM and define the genetic interval into which this mutation maps.

Animals↗

Recombination events that locate myotonic dystrophy distal to APOC2 on 19q.

We previously reported a recombination in an individual with myotonic dystrophy (DM) which placed the markers D19S19 and APOC2 on the same side of the DM locus. Haplotyping of this family with more recently characterized probes which are either tightly linked to DM or distal to the linkage group at q13.2 shows that the DM locus is distal to APOC2. This is confirmed by other recombinants where DM segregates with distal probes. Additional marker to marker recombinations in unaffected individuals are reported and support the order and orientation of the DM linkage group as pter-(INSR, LDLR,S9)-(S19,BCL3,APOC2)-(CKMM,DM)-(S22,+ ++PRKCG)-qter. The data presented here cannot determine whether DM is proximal or distal to CKMM. The consequences of this probe order for antenatal diagnosis and future research aiming to isolate the gene which is affected in DM are discussed.

Chromosome Mapping↗

Segregation of linked probes to myotonic dystrophy in a family demonstrating that 152 and APOC2 are on the same side of DM on 19q.

The two markers most closely linked to the myotonic dystrophy (DM) locus on chromosome 19 are the gene that codes for apolipoprotein CII (APOC2) and the anonymous probe D19S19 (LDR152). Both of these markers show tight linkage to DM, with maximum lod scores of greater than 20 at recombination fractions of less than 0.05. We have identified, in a family in which DM segregates, an affected individual where a meiotic recombination event has occurred in which both of these linked markers have crossed over with the gene defect. This demonstrates that APOC2 and D19S19 are probably on the same side of DM.

Chromosome Mapping↗

DNA polymorphisms within the porphobilinogen deaminase gene in two Swedish families with acute intermittent porphyria.

Two unrelated families with acute intermittent porphyria (AIP), an autosomal dominant disease related to a defect in porphobilinogen deaminase (PBG-D, EC 4.1.3.8.), were studied with regard to three restriction fragment length polymorphisms (RFLPs) (MspI, PstI, BstNI) within the PBG-D gene. The results indicate that linkage analysis of RFLPs within the gene can be used as a complement to PBG-D analysis for the diagnosis of gene carriers in families with AIP.

Ammonia-Lyases↗

DNA linkage analysis of X-linked retinoschisis.

Four families with juvenile retionoschisis (RS) have been studied by linkage analysis utilizing eleven polymorphic X-chromosomal markers. The results suggest a close linkage between DXS43, DXS41, and DXS208 and the RS locus at Xp22. The RS locus is distal to the OTC locus, DXS84, and the DMD locus but proximal to DXS85. No recombination events were observed between the RS locus and DXS43 and DXS41. The maximum likelihood estimate of the recombination fraction (theta) was thus zero and the peak lod scores (z) were 4.98 (DXS43) and 4.09 (DXS41). The linkage data suggest that the gene order on Xp is DXS85-(DXS43, RS, DXS41)-DMD-DXS84-OTC.

Chromosome Mapping↗

A linkage study of the locus for X-linked Charcot-Marie-Tooth disease.

A large family with Charcot-Marie-Tooth disease, showing a probable X-linked incomplete dominant inheritance, was studied by linkage analysis. Results, obtained by the use of X chromosome specific DNA probes of known regional location, suggest that the disease locus is linked to the DXYS1 locus (z = 2.59 at theta = 0.00) and to the DXS14 locus and, places the disease locus between the DXYS1 locus and the DXS14 locus, near the centromere of the X chromosome. Together with the published data, a distance of 13 cM (z = 6.95) was assessed between the disease locus and the DXYS1 locus.

Charcot-Marie-Tooth Disease↗