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Alejandro Giraldo

Publications and source records attributed to Alejandro Giraldo.

7 recordsLinked to original sources
PubMed2005

MLH1 and MSH2 mutations in Colombian families with hereditary nonpolyposis colorectal cancer (Lynch syndrome)--description of four novel mutations.

This study searched for mutations in the MLH1 and MSH2 genes in 23 unrelated Colombian families with suspected hereditary nonpolyposis colorectal cancer (HNPCC). The families were grouped according to the fulfillment of the Amsterdam II criteria or the Bethesda guidelines. We screened all probands by single-strand conformational polymorphism (SSCP) and direct DNA sequencing. Eleven families fulfilled the Amsterdam criteria II and 12 families the Bethesda guidelines. Germline mutations were detected in 11 families, which corresponds to a mutation detection rate of 48%. When only families fulfilling the Amsterdam II criteria were analyzed, the mutation detection rate rose to 82%. Only 8% of the mutation detection rate was found in families following the Bethesda guidelines. Three mutations were shared by two different families, which corresponds to a total of eight different mutations, seven of them found in the MLH1 gene and one in the MSH2 gene. We have identified four mutations that have not been previously reported to the International Collaborative Group of HNPCC. Three of these are pathogenic, a single base substitution (C > T) at codon 640, exon 17, a G deletion at codon 619, exon 16 and in the MLH1 gene and a two-nucleotide deletion (TG) at codon 184, exon 3 in the MSH2. Also, an unclassified variant, a substitution (C > G) at the codon 141, exon 5 of the MLH1, was detected.

Adaptor Proteins, Signal Transducing↗
PubMed2005

[Identification of point mutations in the 21-hydroxylase gene in patients affected with congenital adrenal hyperplasia].

INTRODUCTION: Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder due to impaired cortisol secretion. Approximately 95% of CAH cases are caused by defects in the 21-hydrodylase2 (CYPA2) gene. The spectrum of clinical manifestations includes a severe and mild form of expression. The frequency of the following point mutations was determined: P30L, IVS2-12A/C-G splice, Del 8pb, I172N, cluster Ex6, V281L, Q318X, R356W and P453S. MATERIALS AND METHODS: The 58 patients consisted of 48 with the severe form of CAH and 10 with the mild form. Point mutations in the hydroxylase gene were isolated by allele-specific PCR and PCR-ACRS (amplification created restriction site), and their frequency was determined. RESULTS: Alternate alleles were identified in 82.8% of the samples. The most frequent mutations were IVS2-12A/C-G splice (26.7%), Q318X (21.5%), V281L (12.1%) and I172N (12.1%). DISCUSSION: The most frequent mutations were similar to those observed in other countries, except for Q318X. Although its frequency was higher but similar to that observed in Latin American countries, it contrasted with those of other continents and indicated the possible influence of genetic background in its expression. Several of the mutations were associated with specific clinical forms related to the enzyme activity. In the milder forms of CAH, several alleles were detected. These were important because these patients can have children with the virilizing and salt wasting forms. Recognition of the allelic forms of CAH will permit more specific genetic counseling and prenatal diagnosis.

Adrenal Hyperplasia, Congenital↗
PubMed2005

[Detection mutations in the DNA mismatch repair genes of hMLH1 and hMSH2 genes in Colombian families with suspicion of hereditary non-polyposis colorectal carcinoma (Lynch syndrome)].

INTRODUCTION: Colorectal cancer (CRC) is the second highest cause of cancer mortality in developed countries. In Colombia, CRC ranks fifth as a cause of cancer death. Approximately 75% of CRC appear to be spontaneous and 25% are familial, with 5% of the latter clearly hereditary. Of these, hereditary non-polyposis colorectal carcinoma (HNPCC)-or Lynch syndrome is the most important. OBJECTIVE: Herein, the two most important genes involved in Lynch syndrome, the hMLH1 and hMSH2 were analyzed for presence of mutations. MATERIALS AND METHODS: Seventeen Colombian families that fulfilled the Amsterdam II criteria or Bethesda guidelines for Lynch syndrome were selected. The of 35 exons of hMLH1 and hMSH2 genes were screened by SSCP and those with electrophoretic variants were sequenced. RESULTS: Eight germinal mutations were detected, corresponding to a 47% detection mutation rate. Six of the eight mutations have previously been reported. These consisted of the following mutations: a single base substitution at the donor splicing site of exon 9, a single base substitution (A>G) at codon 755 of the exon 17, and another single base substitution (G>A) at codon 681 of exon 18. The two novel mutations consisted of a single base substitution (C>T) at codon 640 of exon 17 of the hMLH1 gene and a two-nucleotide deletion (TG) at codon 184 of exon 3 of hMSH2 gene. In addition, two families were observed with a polymorphism in the intron 13 (G>A) nt 1558+14, of hMLH1 gene. CONCLUSIONS: This study represented the first survey for detecting mutations associated with Lynch syndrome in Colombia, and is intended to lead to the establishment of a management and prevention program.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Genetic services in Colombia.

Medical genetic services, including clinical genetics, cytogenetics, biochemical and molecular genetics and paternity testing, are performed in Colombia in the more developed medical schools or university institutions, in nine major cities of the country. Accessibility to genetic services is limited by medical care reimbursement laws which do not cover clinical genetic services nor genetic tests. Paternity testing is performed free of charge by a governmental welfare institution, if a legal claim is made against an alleged father. Basic teaching of genetics in medical schools is mandatory, but is very uneven and limited to the better schools. Postgraduate medical genetic training is offered by four different programs of similar quality. Research is performed on some of the most prevalent genetic conditions and on population genetic issues.

Colombia↗
PubMed2003

[Frequency of congenital anomalies at the Instituto Materno Infantil, Bogota, Colombia].

At the Instituto Materno Infantil (IMI) in Bogotá (Colombia), 5,686 births (5,597 live births and 89 stillbirths) were analyzed during two periods: from October, 1997, to April, 1998, and from July to November, 2000 (12 months). Congenital anomalies were detected in 4.4% of live newborn babies and in 7.8% of stillbirths. Major anomalies corresponded to 69% and mild anomalies to 31% (3% and 1.4% of all live births, respectively). The newborn babies with major anomalies, in comparison to the normal controls, had higher mortality at hospital discharge (p = 0.0001), lower average birth weight (p = 0.003), and family history of congenital anomalies (p = 0.0001). The only significant association for mild anomalies was with family history of congenital anomalies (p = 0.0001). The frequency of congenital anomalies was similar to that in other studies, although certain kinds of anomalies showed noticeable frequency differences. This may be a consequence of differences in record keeping or in detection methods.

Adolescent↗
PubMedDate not supplied

[Basic standards for Colombian paternity testing laboratories, 2005].

The Commission for Accreditation and Surveillance of Laboratories Practicing DNA Paternity Tests (created by the Colombian Law 721/2001) set up sub-commission to review the current basic Colombian standards required for paternity testing laboratories and make specific recommendations re the pertinent technical aspects in Colombia, taking ISO 17025 as current reference. This document contains such recommendations for Colombia.

Colombia↗