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X Estivill

Publications and source records attributed to X Estivill.

At least 289 records · Page 16Linked to original sources
PubMed1992

Mutation analysis of genetic diseases by asymmetric-PCR SSCP and ethidium bromide staining: application to neurofibromatosis and cystic fibrosis.

The Single Strand Conformation Polymorphism (SSCP) technique is widely used in mutation analysis. We have introduced several modifications to the SSCP method, which overcome the problem of incomplete denaturation or reannealing of DNA during electrophoresis. The modifications consist of asymmetrical PCR amplification of the sequence of interest, electrophoresis with a higher concentration of acrylamide, and the analysis of the DNA fragments under u.v. light. We have applied this method to the analysis of two specific diseases: neurofibromatosis type 1 (NF1) and cystic fibrosis (CF) from PCR amplified exons. Two single nucleotide changes were observed with this method.

Base Sequence↗
PubMed1992

Cystic fibrosis in the Basque country: high frequency of mutation delta F508 in patients of Basque origin.

The Basque population is one of the oldest populations of Europe. It has been suggested that the Basques arose from a population established in western Europe during the late Paleolithic Age. The Basque language (Euskera) is a supposedly pre-Indo-European language that originates from the first settlers of Europe. The variable distribution of the major cystic fibrosis (CF) mutation (delta F508 deletion) in Europe, with higher frequencies of the mutation in northern Europe and lower frequencies in southern Europe, has suggested that the delta F508 mutation was spread by early farmers migrating from the Middle East during the Neolithic period. We have studied 45 CF families from the Basque Country, where the incidence of CF is approximately 1/4,500. The birthplaces of the parents and grandparents have been traced and are distributed according to their origin as Basque or Mixed Basque. The frequency of the delta F508 mutation in the chromosomes of Basque origin is 87%, compared with 58% in those of Mixed Basque origin. The analysis of haplotypes, both with markers closely linked to the CF gene and with intragenic markers, suggests that the delta F508 mutation was not spread by the Indo-European invasions but was already present in Europe more than 10,000 years ago, during the Paleolithic period.

Biological Evolution↗
PubMed1991

Recurrence of a nonsense mutation in the NF1 gene causing classical neurofibromatosis type 1.

The gene responsible for von Recklinghausen neurofibromatosis (NF1) has recently been identified, and several point mutations and deletions have been described. The availability of intron-exon boundaries of several exons of the NF1 gene facilitates the search for mutations in affected patients. We have analysed 38 patients for mutations in exon 4 of the NF1 gene, and found one patient with a C----T transition at base position 1087 of the cDNA, changing an arginine codon to a stop codon, at amino acid position 365. Sequencing of other members of the family, including both parents, did not show the mutation, confirming that this mutation is responsible for this sporadic NF1 case. As the mutation described here was previously identified in an independent case by others, this case represents a recurrence of this mutation and suggests that codon 365 might be a hot spot for mutations in the NF1 gene. Thus, a specific search for this mutation should be performed when studying NF1 sporadic or familiar cases for genetic analysis.

Amino Acid Sequence↗
PubMed1991

High conservation of sequences involved in cystic fibrosis mutations in five mammalian species.

Several mutations have been identified in the first nucleotide binding fold (NBF) of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene. We have analyzed the DNA sequences of exons 10 and 11 in five different mammalian species, marmoset, mouse, cow, pig, and sheep; the amino acid conservation studied for nine disease mutations; and two "benign" mutations. For exon 10, 87% homology at the DNA level and 93.5% at the amino acid level were found for these species. For exon 11, the lowest homology (70%) was found in mouse and the highest in marmoset (93%), whereas the amino acid sequence conservation ranged from 82.5 to 100%. All codons involved in CF mutations are highly conserved throughout evolution.

Amino Acid Sequence↗
PubMed1991

CA/GT microsatellite alleles within the cystic fibrosis transmembrane conductance regulator (CFTR) gene are not generated by unequal crossingover.

The gene responsible for cystic fibrosis (CF) has recently been identified, and a three-nucleotide deletion (delta F508 mutation) that results in the loss of a phenylalanine residue in the first putative ATP-binding domain of the predicted protein (CF transmembrane conductance regulator, CFTR) has been found to be the major CF mutation. Although several other mutations have been identified in the CFTR gene, most of them are very rare, making their application to genetic diagnosis difficult. While characterizing the genomic region encompassing the CF locus, we have identified three CA/GT blocks that flank exon 9 of the CF gene. One of the CA/GT blocks exhibits a highly informative variable number of dinucleotide repeats (VNDR) polymorphism. This intragenic VNDR microsatellite should, by itself, provide full information for genetic analysis in approximately 80% of CF families and will help elucidate the associations between DNA polymorphism haplotypes and specific gene mutations. Haplotype analyses of CF chromosomes with and without the delta F508 mutation suggest that the different alleles are generated by slipped-strand mispairing within the dinucleotide repeat during DNA replication, rather than by unequal crossingover within a recombination hot spot.

Alleles↗
PubMed1991

Mutation and linkage disequilibrium analysis in genetic counselling of Spanish cystic fibrosis families.

We have analysed haplotypes for four DNA polymorphisms, closely linked to the cystic fibrosis (CF) gene, in 82 Spanish families, in which the CF probands are either homozygous for non-delta F508 mutations or heterozygous for the delta F508 deletion and other CF mutations. The analysis provides genetic data for a new polymorphism for the closely linked marker pKM.19, which is very strongly associated with CF. Haplotypes generated with the four marker loci are also in strong disequilibrium with the non-delta F508 CF chromosomes. The data reported here are useful in 1 in 4 risk pregnancies of parents who have no living affected child, and when counselling close relatives of CF families who are negative for the major CF mutation. The data presented are useful in our population, in which the majority of CF mutations, apart from the delta F508 deletion, are uncommon. For other populations in which mutation heterogeneity is also very high, it still might be more feasible to use RFLPs for diagnostic purposes, when analysis for common mutations is negative and DNA is available from the index patient. The experience presented here provides a model for these population groups who in turn should obtain their own haplotype data. In addition, the model system for genetic counselling presented here might also be useful for other genetic disorders.

Chromosome Deletion↗
PubMed1990

[Use of the polymerase chain reaction technic in the genetic analysis of cystic fibrosis].

The development of polymerase chain reaction (PCR) which allows the specific amplification of DNA sequences has improved considerably the genetic analysis of hereditary diseases. We present here the application of this new technique to the genetic analysis of cystic fibrosis (CF), the most frequent severe genetic disease in caucasians. We have amplified four sequences containing polymorphisms linked to the CF gene (CS.7, KM.19, MP6d-9 and J3.11), and analysed the amplified products with restriction enzymes. Complete concordance was found with classical Southern methods, allowing the application of PCR to routine CF family studies.

Amino Acid Sequence↗