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M Baiget

Publications and source records attributed to M Baiget.

At least 55 records · Page 3Linked to original sources
PubMed2001

Conditions for single-strand conformation polymorphism (SSCP) analysis of BRCA1 gene using an automated electrophoresis unit.

The single-strand conformation polymorphism procedure has been applied in routine testing for hereditary diseases and cancer. However, temperature, running time, gel composition, fragment length, etc. can influence its sensitivity. Mutation detection in the clinical setting depends on the development of automated technology, especially for large genes such as the breast cancer gene BRCA1. We analysed DNA samples with BRCA1 mutations in an automated system (GenePhor System; Amersham-Pharmacia Biotech, Uppsala, Sweden). The concentrations of DNA template and PCR primers, the effect of chilling after denaturation, and the temperature and time of the electrophoresis were investigated. All band-shifts were detected by electrophoresis at 5 degrees C for 2 h 15 min. Concentrations of DNA and samples used in the PCR did not affect the SSCP pattern, but chilling the PCR product in ice after denaturation was required. The type and position of mutation in the fragments did not influence the probability of a mobility shift, although SSCP analysis was more sensitive for fragments shorter than 350 bp. This automated SSCP method meets the requirements of fast turnaround and sensitivity and can be readily adapted to the screening of large genes such as BRCA1.

BRCA1 Protein↗
PubMed2001

Distal anterior compartment myopathy: a dysferlin mutation causing a new muscular dystrophy phenotype.

We report a family with a new phenotype of autosomal recessive muscle dystrophy caused by a dysferlin mutation. The onset of the illness is distal, in the muscles of the anterior compartment group. The disease is rapidly progressive, leading to severe proximal weakness. Muscle biopsy showed moderate dystrophic changes with no vacuoles. Dysferlin immunostaining was negative. Gene analysis revealed a frameshift mutation in the exon 50 (delG5966) of the DYSF gene. This phenotype further demonstrates the clinical heterogeneity of the dysferlinopathies.

Adult↗
PubMed2000

[Mutational analysis of p53 in T-cell lymphoblastic leukemia].

BACKGROUND: p53 mutations were analysed in a consecutive series of patients with T-ALL from one hospital over a period of 9 years. PATIENTS AND METHOD: Thirty two samples from 27 patients with T-ALL were included in the study. Exons 5-9 were analysed using SSCP. RESULTS: A mutation at codon 273 was identified in a child in third relapse. The mutated clone became dominant in a sample obtained one month following a course of salvage chemotherapy. CONCLUSION: p53 mutations are not frequent in T-ALL even in patients at relapse.

Adolescent↗
PubMed2000

[Aplasia after azathioprine administration: role of the thiopurine methyltransferase genetic polymorphism].

BACKGROUND: Azathioprine is an immunosuppressor drug widely used in the treatment of autoimmune diseases. Adverse effects during treatment are related to the activity of thiopurine methyltransferase (TPMT), an enzyme which plays a role in azathioprine metabolism. The presence of the allelic variants of the TPMT gene allows us to classify patients into three different groups: high, moderate and low risk of myelosuppression after receiving standard doses of azathioprine. PATIENTS AND METHODS: Study of the allelic variants of the TPMT gene in the positions 460 and 719 with PCR methods in a patient with Crohn's disease, who developed aplasia after receiving azathioprine. The study was extended to his relatives. RESULTS: The patient under study carried the most frequent variant allele of the TPMT gene associated with low enzymatic activity. The mother and one sister of the patient were also carriers of this allelic variant. CONCLUSIONS: Genotyping the allelic variants of the TPMT gene is a useful method to identify patients at moderate or high risk of myelosuppression after administration of azathioprine.

Adult↗
PubMed2000

BRCA2 germ-line mutations in Spanish male breast cancer patients.

BACKGROUND: Mutations in the BRCA2 gene account for the majority of the families with male and female breast cancer cases, and a number of BRCA2 mutations have been reported in males with breast cancer. The aim of this study was to characterise BRCA2 germ-line mutations in Spanish male breast cancer patients. PATIENTS AND METHODS: We screened DNA from 11 affected men and 6 women with breast cancer (BC) who had an affected male relative (father or brother). Exons 2-9 and 12-27 were screened by SSCP, and exons 10 and 11 were screened by PTT. PCR products with a variant band were sequenced. RESULTS: Three BRCA2 frameshift mutations were identified (17.6%): the 3374delA in codon 1049 (exon 11), 6857delAA in codon 2010 (exon 11), and 9254delATCAT in codon 3009 (exon 23). These mutations were present in patients with affected first-degree relatives (3 of 9, 33%). The proportion of male patients with a family history of BC in at least one first-degree relative was 53%. CONCLUSIONS: There is an association between BRCA2 mutations and male breast cancer, especially in those with a family history of BC. The high prevalence of BRCA2 mutations among males should be considered when estimating risk for female relatives. All new male cases of BC should be regarded as being possibly inherited and should be fully investigated.

Adult↗
PubMed2000

Complex patterns of male germline instability and somatic mosaicism in myotonic dystrophy type 1.

The genetic basis of myotonic dystrophy type 1 (DM1) is the expansion of a CTG repeat in the 3' untranslated region of DM1PK. Once into the disease range, the repeat becomes highly unstable and is biased toward expansion in both somatic and germline tissues. Intergenerational differences usually reveal an increase in allele length, concordant with the clinical anticipation characteristic of DM1, but there have also been cases with intergenerational contractions of the repeat length, accompanied by apparent anticipation. In order to gain a better understanding of this intergenerational behaviour, we have obtained semen samples from six DM males and used single molecule analyses to compare the allele distributions present in their sperm and blood with those of their offspring. We have confirmed that the male germline mutational pathway is distinct from that of the soma, but the extent of variation is highly variable from one individual to another and not obviously correlated with progenitor allele length. Nonetheless, in all cases the alleles present in the father's sperm overlap with those observed in their offspring. These data also provide further indications that the interpretation of intergenerational transmissions by standard analyses is frequently compromised by the masking of germline differences by age-dependent somatic expansion in the parent.

Adolescent↗
PubMed2000

Allelic variants of the thiopurine S-methyltransferase deficiency in patients with ulcerative colitis and in healthy controls.

OBJECTIVE: Thiopurine S-methyltransferase (TPMT) is a cytosolic enzyme that catalyzes the inactivation of mercaptopurine, azathioprine, and thioguanine. The genetic polymorphisms in the TPMT gene that regulate TPMT activity are inherited as an autosomal recessive trait and patients with genetically determined low levels of TPMT activity develop severe myelosuppression when treated with standard doses of the above-mentioned drugs. We have analyzed the frequencies of the allelic variants of the TPMT gene in a white European population of healthy blood donors from Spain and The Netherlands, and in a group of patients suffering from ulcerative colitis (UC) with a similar genetic background. METHODS: Two hundred and thirteen unrelated healthy individuals (HC) and 146 UC patients were typed for the polymorphic sites at positions 460 (G-->A) and 719 (A-->G) of the TPMT gene using specific polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) methods. RESULTS: There were no significant differences between the allele frequencies observed in the group of UC patients and those of the control group (10% of cases were heterozygous carriers of a TPMT mutant allele). The most frequent mutant allele in both UC and HC groups was TPMT3A (A460-->G719) (60% of carriers). TPMT3B (A460-->A719) and TPMT3C (G460-->G719) alleles were more often found in our study than in previously reported studies, reflecting the different genetic backgrounds of the European populations analyzed. CONCLUSIONS: Genotyping methods provide a simple and reliable screening to identify patients with a high risk of developing severe bone marrow toxicity if treated with thiopurine drugs. In UC patients, TPMT genotype should be determined before the initiation of azathioprine therapy.

Alleles↗
PubMed2000

Prevalence of 2314delG mutation in Spanish patients with Usher syndrome type II (USH2).

The Usher syndrome (USH) is a group of autosomal recessive diseases characterized by congenital sensorineural hearing loss and retinitis pigmentosa. Three clinically distinct forms of Usher syndrome have so far been recognized and can be distinguished from one another by assessing auditory and vestibular function. Usher syndrome type II (USH2) patients have congenital moderate-to-severe nonprogressive hearing loss, retinitis pigmentosa, and normal vestibular function. Genetic linkage studies have revealed genetic heterogeneity among the three types of USH, with the majority of USH2 families showing linkage to the USH2A locus in 1q41. The USH2A gene (MIM 276901) has been identified: three mutations, 2314delG, 2913delG, and 4353-54delC, were initially reported in USH2A patients, the most frequent of which is the 2314delG mutation. It has been reported that this mutation can give rise to typical and atypical USH2 phenotypes. USH2 cases represent 62% of all USH cases in the Spanish population, and 95% of these cases have provided evidence of linkage to the USH2A locus. In the present study, the three reported mutations were analyzed in 59 Spanish families with a diagnosis of USH type II. The 2314delG was the only mutation identified in our population: it was detected in 25% of families and 16% of USH2 chromosomes analyzed. This study attempts to estimate the prevalence of this common mutation in a homogeneous Spanish population.

Alleles↗
PubMed2000

The S65C mutation in Spain. Implications for iron overload screening.

Hereditary hemochromatosis is related to mutations of the HFE gene. The role of the S65C mutation of this gene was evaluated in a Spanish population, consisting of 100 controls and 41 patients who had resulted positive to screening for iron overload. Only one patient was heterozygous for the S65C mutation, so the S65C mutation is infrequent in our area. Nevertheless, it is advisable to search for this mutation in cases with iron overload and heterozygosity for the C282Y or H63D mutations of the HFE gene.

Case-Control Studies↗
PubMed2000

[Molecular basis of spinal muscular atrophy: th SMN gene].

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration and loss of motor neurons of the anterior horn of the spinal cord. The clinical manifestations include proximal symmetric weakness and progressive atrophy of muscle. SMA is classified by age of onset, severity of symptoms, and evolution in three groups: type I, severe or Werdnig-Hoffmann disease, type II or intermediate and type III, moderate-mild, Kugelberg-Welander disease. The identification of the SMN1 gene as determinant of SMA opened new alternatives to study the disease. Most of the patients have deletions and conversion of SMN1 and in a small number of cases, point mutations were detected. There is no obvious genotype-phenotype correlation because homozygous absence of SMN1 was associated to a wide spectrum of manifestations from congenital disease to non symptomatic cases. Modifier factors, such as the number of copies of SMN2, could influence the phenotype. Other possible modifier genes are under study. The SMN gene is expressed in various neuronal populations. However, only motor neurons are responsible for the manifestations of the disease. The SMN protein is part of a complex with various proteins involved in the splicing reaction. This apparent essential function for all cells could be critical in motor neurons. When SMN1 is absent or dysfunctional, the motor neurons could be more sensitive because they have an increased transcription activity. In this situation, other cells and tissues could be protected by genetic or cellular factors still undiscovered.

Alleles↗
PubMed1999

BRCA1 mutation analysis in 83 Spanish breast and breast/ovarian cancer families.

A group of 83 Spanish BC/OC families were analysed for BRCA1 germ-line mutations. Analysis of the entire coding sequence was carried out by SSCP and PTT. We identified 5 frameshift mutations: 185delAG (2 times), 189insTGTC, 1241delAC, and 5537delA and 3 missense mutations in BRCA1: 330A > G, 1240C > T, and 5263G > A. The 185delAG mutation was identified in 2 families. One of them was the only Gypsy family participating in our study. All carriers shared the known founder haplotype, although they did not have any Jewish ancestry. Three frameshift mutations were found among the 14 families with 3 or more BC cases and 1 or more OC, which results in a higher percentage (21.4%) of BRCA1 mutations in this group of high risk families. Two missense mutations were found in families with 2 or 3 BC and no OC, indicating a low proportion (4.8%) of mutations in these families. There was no association between bilateral BC and a mutation carrier status. The frequency of BRCA1 involvement is lower than that of any other country hitherto reviewed. Our results highlight the influence of geographical and ethnic origin of the population studied.

Adult↗
PubMed1999

Two contiguously located germline BRCA1 mutations in a Spanish early-onset breast cancer family.

We identified two BRCA1 mutations in a high risk breast cancer family: the missense 1240 C > T (Thr > Ile) and the 1241delAC at codon 374, which results in a stop at codon 376. Both were contiguously located in the same BRCA1 gene, in a motif of 11 amino acids, which is highly conserved across human, canine and murine species. The presence of missense mutations in this motif in breast-cancer families suggests an important functional role for this protein region and a potential deleterious effect of the 1240C > T mutation.

Animals↗
PubMed1999

[The identification of a new mutation in the BRCA2 gene by protein truncation analysis in a Spanish family with hereditary breast cancer].

The BRCA2 mutations are implicated in a high percentage of hereditary breast cancer cases. We report a novel mutation in a Spanish breast cancer family. We analyzed DNA samples of the proband and of the living first and second degree relatives. Exon 11 of BRCA2 gene were screened by the protein truncation test and direct sequencing. We identified a novel mutation, 6857 delAA, in three affected women, diagnosed of breast cancer at 29, 51 and 45 years of age, respectively, and in a healthy male. The BRCA2 mutation seems to be implicated in the development of early-onset breast cancer cases in this family. Identification of this novel mutation adds to the information on BRCA2 gene in hereditary breast cancer in Spanish population.

Adult↗
PubMed1999

[Mutations in the BRCA1 gene in young Spanish women with breast cancer].

BACKGROUND: Germline mutations in the BRCA1 gene have been associated with familial breast/ovarian cancer. Furthermore, women diagnosed of early-onset breast cancer have a higher probability of being carriers of BRCA1 mutations. Our aim was to know prevalence of BRCA1 mutations in women with breast cancer diagnosed before 40 years. PATIENTS AND METHODS: We analyzed genomic DNA samples of 159 women with early-onset breast cancer. Ten fragments of BRCA1 gene covering the 36% of cases with mutations described in the literature were screened. Analysis involved polymerase chain reaction (PCR), single-strand conformation polymorphisms (SSCP) and direct sequencing. RESULTS: Three germline BRCA1 mutations were identified, one of them not previously described. Two mutations were found in women with familial history of breast cancer. Five additional rare variants and polymorphisms were also detected. CONCLUSIONS: The absence of recurrent mutations or mutations detected in other countries, except for the 185delAG mutation, present in Ashkenazim population, shows the influence of ethnic and geographic origin of population studied, and illustrates the difficulties of establishing DNA-based screening tests for hereditary breast cancer.

Adolescent↗