FRAXA locus in fragile X diagnosis: family studies, prenatal diagnosis, and diagnosis of sporadic cases of mental retardation
| Autor: | Maarit Peippo, H von Koskull, A Salo, Nina Gahmberg, Riitta Salonen |
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| Rok vydání: | 1994 |
| Předmět: |
Male
medicine.medical_specialty X Chromosome DNA Mutational Analysis Chorionic villus sampling Prenatal diagnosis Locus (genetics) Biology Methylation Diagnosis Differential 03 medical and health sciences Predictive Value of Tests Intellectual Disability Prenatal Diagnosis Tissue mosaicism medicine Humans Allele Genetics (clinical) 030304 developmental biology Genetics 0303 health sciences Fetus medicine.diagnostic_test Obstetrics Mosaicism Chromosome Fragility Genetic Carrier Screening 030305 genetics & heredity medicine.disease Fragile X syndrome Chorionic Villi Sampling Fragile X Syndrome Amniocentesis Female DNA Probes Dinucleoside Phosphates |
| Zdroj: | American journal of medical genetics. 51(4) |
| ISSN: | 0148-7299 |
| Popis: | Three hundred eighty-seven individuals from 32 Finnish fragile X families were studied, using the probe StB12.3 [Oberle et al., 1991: Science 252:1097-1102] for the FRAXA locus, to reveal length variations in the FMR-1 gene. As expected, the affected individuals (with few exceptions) showed a full mutation; a few affected individuals with a premutation only were found. Seventy percent of the females with a full mutation were affected. The size of the mutation remained unchanged in 6, increased in 73, and decreased in 6 female meioses. In male meioses the size was unchanged in 15 cases, increased in 2 cases, and decreased in 1 case. Prenatal diagnosis was performed in 20 cases. In 7 of these the mutation was inherited by the fetus. Four hundred sixty-four mentally retarded patients were referred to us for FRAXA analysis. In 5% of these the fragile X mutation was found. In addition to the clear cut negative or positive results there were 6 cases in which an increase of 50-80 bp was detected. These findings may represent either large normal alleles or small premutations suggesting a possible tissue mosaicism which could explain the retardation of the patients. |
| Databáze: | OpenAIRE |
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