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Start Over Author "Ballesta, F." Journal human genetics
5 results on '"Ballesta, F."'

4. Molecular analysis of the (CGG)n expansion in the FMR-1 gene in 59 Spanish fragile X syndrome families

Author

Milà, M., Kruyer, H., Glover, G., Sánchez, A., Carbonell, P., Castellví-Bel, S., Volpini, V., Rosell, J., Gabarrón, J., López, I., Villa, M., Ballesta, F., and Estivill, X.

Abstract

The fragile X mental retardation syndrome is caused by an expansion of a trinucleotide repeat (CGG)n in the FMR-1 gene. Molecular genetic study of fragile X provides accurate diagnosis and facilitates genetic counseling in families with affected members. We present here the molecular study of 59 Spanish fragile X syndrome families using probe StB 12.3 and the polymerase chain reaction (PCR) of the (CGG)n repeat sequence of the FMR-1 gene. The results obtained have allowed us to characterize 455 individuals, including eight prenatal diagnoses. The clinical diagnosis of fragile X in 89 affected males was confirmed, 137 female carriers were identified (48 of whom were mentally retarded), 176 individuals “at risk” were found not to have the expansion, and 12 cases of normal transmitting males (NTM) were detected. In the sample studied, no de novo mutations were detected, nor any mutation different from that described for the (CGG)n expansion. One nonmentally retarded male was detected as having an unmethylated CpG island for the FMR-1 gene, but with more than 200 CGG repeats (high functioning male). The analysis of the (CGG)n repeat in 208 normal chromosomes gave an allele distribution similar to that in other Caucasoid population groups, with alleles of 29 and 30 CGG repeats accounting for 46% of the chromosomes. The combination of Southern analysis and PCR of the (CGG)n repeat is highly efficient for diagnosis, compared with cytogenetic techniques, especially in the detection of female carriers, NTMs, and prenatal diagnosis, enabling accurate genetic counseling to be provided in all cases.

Published
1994
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5. YAC and cosmid FISH mapping of an unbalanced chromosomal translocation causing partial trisomy 21 and Down syndrome.

Author

Nadal M, Milà M, Pritchard M, Mur A, Pujals J, Blouin JL, Antonarakis SE, Ballesta F, and Estivill X

Subjects
Adult, Base Sequence, Child, Chromosome Mapping, Chromosomes, Artificial, Yeast, DNA Primers, Face abnormalities, Female, Genetic Markers, Humans, In Situ Hybridization, Fluorescence, Infant, Intellectual Disability genetics, Karyotyping, Male, Molecular Sequence Data, Monosomy, Phenotype, Polymerase Chain Reaction, Tooth Abnormalities genetics, Chromosomes, Human, Pair 13, Chromosomes, Human, Pair 21, Down Syndrome genetics, Translocation, Genetic, Trisomy
Abstract

Most cases of Down syndrome (DS) result from a supernumerary chromosome 21; however, there are rare cases in which DS is due to partial trisomy of chromosome 21, involving various segments of the chromosome. The characterization of cases of DS that are due to partial trisomy 21 allows the phenotype to be correlated with the genotype. We present a case with features of DS and a partial trisomy of chromosome 21 inherited from a paternal balanced translocation involving chromosomes 13 and 21. Fluorescence in situ hybridization analysis using yeast artificial chromosome (YAC) probes mapped the breakpoint to 21q22.1, within YAC 230E8, which contains markers CBR, D21S333 and D21S334. Further mapping using cosmids positioned the breakpoint proximal to CBR. The patient was also monosomic for the distal portion of chromosome 13 (q33-qter). Many phenotypic features of DS were present including hypotonia, flat occiput, flat facies, up-slanted palpebral fissures, epicanthic folds, flat nasal bridge, macroglossia, open mouth, small ears and a heart murmur. This case further supports the contention that the majority of the phenotypic features of DS map to 21q22-qter and further refines the location of some of them. In addition to the DS phenotype, the patient had a prominent upper maxilla with protruding upper incisors, and low levels of the coagulation factors VII and X, consistent with a syndrome resulting from monosomy 13q33-qter. Since some features overlap between the two syndromes, including severe mental retardation, it is unclear to what extent monosmy for 13q33-qter, trisomy for 21q22.1-qter, or a combination of both, contributed to the common features of the phenotype.

Published
1996
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