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F Prieto

Publications and source records attributed to F Prieto.

At least 55 records · Page 3Linked to original sources
PubMed1995

Prenatal diagnosis of Friedreich ataxia: improved accuracy by using new genetic flanking markers.

Friedreich ataxia is a neurodegerative disorder with autosomal recessive inheritance. Since the gene causing mutation has not yet been identified, prenatal, predictive, and carrier diagnoses are based on indirect haplotype analysis with closely linked markers. Until recently, only distal markers were available and their physical distance to the Friedreich ataxia (FRDA) gene remained elusive. The identification of close flanking markers that mark out the boundaries of the FRDA locus and reduce the critical genomic region which contains the gene allows for the first time misdiagnosis due to undetectable recombination to be avoided and diagnosis accuracy to be greatly improved. In this sense, we have verified a prenatal diagnosis in which the fetus was diagnosed as an unaffected carrier last year with a confidence of 95 per cent. By using the new flanking markers, the diagnosis improved and confidence reached almost 100 per cent.

Adult↗
PubMed1995

An autosomal dominant retinitis pigmentosa family with close linkage to D7S480 on 7q.

Retinitis pigmentosa is the most prevalent inherited disorder of the retina. It can be autosomal dominant (adRP), autosomal recessive (arRP) or X-linked (XLRP). A form of adRP mapping to chromosome 7q was reported in a large Spanish pedigree. We have typed DNA from the members of another Spanish family for polymorphic markers from the known candidate genes. Positive lod scores were obtained only for the markers located on 7q31-35, giving a maximum lod score of 2.98 (3.01 by multipoint analysis) at theta = 0.00 for D7S480. A brief clinical evaluation is given.

Chromosome Mapping↗
PubMed1995

Gly114Asp mutation of rhodopsin in autosomal dominant retinitis pigmentosa.

Two autosomal dominant retinitis pigmentosa families of different origin were screened for rhodopsin mutations using the method of single strand conformation polymorphism and direct sequencing. We found a CGG-CAG substitution in codon 114 of rhodopsin in both families. This change predicted the replacement of a glycine by an aspartic acid and suggested that this change is the cause of the disease in these families.

Adolescent↗
PubMed1994

Mapping of Friedreich's ataxia locus by identification of recombination events in patients homozygous by descent.

The Friedreich's ataxia locus (FRDA) maps on chromosome 9q13. Genetic data, obtained from a small number of recombination events, indicated that the FRDA locus might be located centromeric to the D9S15/D9S5 linkage group, the most probable order being cen-FRDA-D9S5-D9S111-D9S15-D9S110-qter. Recently, new centromeric markers have been reported. Analysis of these markers allowed us to localize the recombination breakpoint in some of the recombinant families. However, only one proximal recombination has been found with these markers. To increase the genetic information from FRDA families, we have analyzed the centromeric markers FR1, FR2, FR7, FR8, and FR5 in patients homozygous by descent. These were ascertained because parents were consanguineous or because they were homozygous for the entire haplotype D9S15 or D9S111-D9S5-D9S411E-D9S202. Haplotype divergence for, at least, two contiguous markers was observed in two patients homozygous for the core D9S111-FR2 haplotype and in one third-degree consanguineous family homozygous for haplotype D9S411E-FR5. Interpretation of divergence as the result of ancient meiotic crossovers allowed the definition of three new recombination events which place the FRDA locus within the interval defined by markers D9S411E and FR8. A consanguineous family with first-cousin parents showed homozygosity only at D9S202 and FR2. Further investigations are needed to discern whether two different mutations are segregating in the family or whether two recombinations, one distal and one proximal, have taken place.

Biomarkers↗
PubMed1993

Cytogenetic, FISH and DNA studies in 11 individuals from a family with two siblings with dup(21q) Down syndrome.

A Spanish family has previously been described with two siblings with dup(21q) Down syndrome. The father has a normal karyotype. The mother has a microchromosome. Cytogenetic, fluorescence in situ hybridization and DNA studies have now been carried out on the family. Findings include that the mother has three different chromosome anomalies, viz. (1) a chromosome 22 with an unusual pericentromeric region that contains alphoid DNA from chromosomes 21/13 and chromosome 22, (2) an isochromosome 21p in the frequent cell line and (3) an isochromosome 21q in a rare second cell line. A possible explanation is that the mother developed from a zygote with trisomy 21 and that mitotic error in early development resulted in the formation of two cell lines with karyotypes of 47,XX,+i(21p) and 47,XX,+i(21q), respectively. The unusual chromosome 22 represents a hitherto undescribed chromosome anomaly and one possible explanation is a translocation of the short arms between chromosomes 21/13 and 22 in the ancestry of the family. The relationship between the unusual chromosome 22 and the isochromosome formation in the mother is not known. However, all three chromosome anomalies involve the alphoid DNA of chromosome 21/13, indicating that this is not a chance finding.

Centromere↗
PubMed1993

Translocation (12;14)(q13;q32) in myelodysplastic syndrome.

We report a patient diagnosed with refractory anemia with excess blasts in transformation (RAEB-t) who underwent an evolution to a nonlymphocytic acute leukemia (ANLL-M5a). Initial cytogenetic study showed a diploid karyotype; however, when ANLL-M5a was diagnosed, the bone marrow (BM) cells showed a t(12;14)(q13;q32), which to our knowledge has not been described previously in a myelodysplastic syndrome (MDS).

Anemia, Refractory, with Excess of Blasts↗
PubMed1993

Origin of the de novo duplication in Charcot-Marie-Tooth disease type 1A: unequal nonsister chromatid exchange during spermatogenesis.

A 1.5 Mb duplication within 17p11.2 is the major mutation causing both autosomal dominant and sporadic Charcot-Marie-Tooth disease type 1A (CMT1A). An independent origin for the mutation in each family has been postulated. The proposed genetic mechanism causing the CMT1A duplication is unequal nonsister chromatid exchange at meiosis (unequal crossing-over). We studied the parental origin of the duplication in nine genetically sporadic CMT1A patients and demonstrated that in all cases the mutation was the product of an unequal nonsister chromatid exchange during spermatogenesis. The fact that only paternal de novo duplications were observed in the sporadic CMT1A patients suggests that male specific factors may be operating during spermatogenesis that either help forming the duplication and/or stabilize the duplicated chromosome.

Blotting, Southern↗
PubMed1992

Acute nonlymphoblastic leukemia in children treated for acute lymphoblastic leukemia with an intensive regimen including teniposide.

Some cases of conversion from acute lymphoblastic leukemia (ALL) to acute nonlymphoblastic leukemia (ANLL) at relapse have been reported recently. We report three cases initially diagnosed as having ALL and showing morphological, cytochemical, and immunophenotypic features of ANLL at relapse (lineage switch). Conversion was observed among 14 patients who developed bone marrow relapse while undergoing intensive treatment with our ALL protocol, which includes teniposide, and that had been administered to 62 patients. The three cases converted at first relapse, with a mean time of 20 months (13-29 months). Clinical and immunologic characteristics of T-cell leukemia were present in one patient. Changes documented in cytogenetic studies are discussed. The underlying mechanisms for the lineage switch remain unclear as does its relation with mixed lineage leukemias, but we believe that drugs employed in our therapy protocol could have had an influence on this conversion.

Child, Preschool↗
PubMed1992

Cytogenetic studies in 112 cases of untreated myelodysplastic syndromes.

Cytogenetic studies were performed in 112 untreated cases of myelodysplastic syndrome (MDS) between 1985 and 1990. Among 112 patients who were examined at the time of diagnosis, 54 had an abnormal karyotype (48%). The highest frequency of chromosome abnormalities was observed in refractory anemia with excess of blasts (RAEB) and RAEB in transformation (RAEB-t) and the lowest in refractory anemia with ring sideroblasts (RARS) and chronic myelomonocytic leukemia (CMMoL). Numerical changes were observed in 19 cases and structural in 17; chromosome 8 was most frequently gained (11 cases), whereas chromosome 7 was most frequently lost (6 cases), 5q- in 14 (4 as a sole anomaly); involvement of 7q22 was seen in 3 cases, 11p in 2 patients, 11q in 3 (one patient as a sole anomaly), 12p in 4 (2 patients as a sole anomaly), i(17q) in 4 (3 patients as a sole anomaly), and complex chromosomal defects in 10 patients. If one takes into account the prognosis value, a complex karyotype and the presence of ring chromosomes were correlated with the worst prognosis, followed by -7/7q-; an intermediate prognosis corresponds to i(17q), 12p as a sole anomaly, +8 (as a sole anomaly or plus other anomalies), and involvement of 12p. Patients with a 5q- as a sole anomaly or with a normal karyotype, had the best prognosis.

Adolescent↗
PubMed1992

A fragile X family with high penetrance in females: risk heterogeneity?

A fragile X family is described which shows two interesting features. In a sibship of seven, the two males and four of the five females are affected with mental retardation. Since the only normal daughter is not a carrier, the penetrance of the fragile X mutation in carrier daughters is 100%. Nevertheless, the penetrance of this syndrome in affected daughters of normal mothers has been estimated at a third. Also, DNA typing analysis of flanking RFLP markers revealed a higher than expected number of crossing-overs. We also include the molecular study of the mutation in the (CGG)n repeat of the FMR-1 gene.

Adolescent↗
PubMed1991

Cytogenetic evidence of involvement of an early progenitor myeloid cell in 4;11 translocation-associated acute leukemia.

The t(4;11)(q21;q23)-associated acute leukemia may show both lymphoid and myelomonocytic features, which suggests a pluripotent progenitor stem cell as the hematopoietic cell involved in this neoplastic process. However, there is no cytogenetic evidence to support this contention. We present a case of acute myelomonocytic leukemia (M4, FAB subtype) with t(4;11)(q21;q23), which was also found in several hypertetraploid metaphases probably corresponding to megakaryocytes. This confirms the cellular origin in an early progenitor myeloid cell of this type of acute leukemia.

Bone Marrow↗
PubMed1991

Chromosome 5 abnormalities in acute lymphoblastic leukemia.

We report two cases of acute lymphoblastic leukemia with involvement of chromosome 5. One of them showed a del(5)(q13q33) in a 5-year-old boy who had previously received antineoplastic chemotherapy for an L1-ALL that had been diagnosed nine months before. The other one showed a t(5;7)(q12-13;q36) together with a t(8;14)(q24;q32) and a der(1) in a 66-year-old man with an L3-ALL. Both chromosome 5 aberrations are interpreted as evolutionary events. In the first case, it was secondary to chemotherapy treatment; in the second, an evolutionary chromosome rearrangement, considering the translocation between chromosomes 8 and 14 as the primary cytogenetic event.

Child, Preschool↗
PubMed1990

[Genetic analysis of Friedreich's ataxia using polymorphic DNA markers].

Friedreich's ataxia (FA) is a progressive degenerative disease involving both central and peripheral nervous system. It is an autosomal recessive hereditary disorder, which begins around puberty and has an unknown genetic basis and biochemical defect. The recent mapping of FA locus in human chromosome 9 by means of the analysis of the molecular genetic linkage has permitted to evaluate FA genetics with polymorphic genetic markers (RFLPs) that are secreted linked with the FA gene. The normal and mutant allele secretion of FA was evaluated in ten Spanish families with one or two members with FA by means of several cloned probes (MCT112, DR47, D9S1 and HHH220), localized in chromosome 9 and strongly linked to FA gene, with the aim of achieving a predictive diagnosis of relatives in the pediatric age and to detect healthy carriers. In 9 out of 10 families some totally or partially informative RFLP were found. In 5 of 6 relatives in pediatric age the future development of the disease could be ruled out. By contrast, the carrier status could only be identified in three relatives. In a family with two affected children a genetic recombinant for D9S1 was found. Remarkably, one of them had a better clinical evolution and preserved tendon reflexes in lower limbs.

Adolescent↗
PubMed1990

11q23 abnormalities in children with acute nonlymphocytic leukemia (M4-M5). Association with previous chemotherapy.

Cytogenetic studies of 12 patients aged less than 14 years with acute nonlymphoblastic leukemia (ANLL) (M4-M5) showed structural abnormalities on chromosome 11 at band q23-q24 in five cases (41.8%). Four of these 12 patients had ANLL (M4-M5) after treatment with cytostatics for non-Hodgkin lymphoma in one case and for an acute lymphoblastic leukemia (ALL) in the other three. Three of these four cases had 11q23 abnormalities [one [one 46,XY,t(11;17)(q23;25); another 47,XY,+8,-15,del(11)(q23),+der(15)t(15;?)(p11;?); the third 47,XX,+8,t(3;17) (p11;q25),t(4;11)(q21;q23)] and one had a normal karyotype on being diagnosed ANLL (M4-M5). The notable increase of ANLL (M4-M5) in our patients who had received cytostatics as treatment for a previous neoplasia makes evaluation of our results timely in comparison with those of other groups who use these therapeutic protocols.

Antineoplastic Agents↗