Monozygotic twin brothers with the fragile X syndrome: different CGG repeats and different mental capacities.
J Med Genet
; 36(3): 253-7, 1999 Mar.
Article
en En
| MEDLINE
| ID: mdl-10204857
ABSTRACT
Little is known about the mechanism of CGG instability and the time frame of instability early in embryonic development in the fragile X syndrome. Discordant monozygotic twin brothers with the fragile X syndrome could give us insight into the time frame of the instability. We describe monochorionic diamniotic twin brothers with the fragile X syndrome who had different CGG repeats and different mental capacities, whereas the normal mother had a premutation. The more retarded brother had a full mutation in all his cells and no FMR-1 protein expression in lymphocytes, whereas the less retarded brother had 50%/50% mosaicism for a premutation and full mutation and FMR-1 protein expression in 26% of his lymphocytes. The differences in repeat size could have arisen either before or after the time of splitting. The time of splitting in this type of twin is around day 6-7. Given the high percentage of mosaicism, we hypothesise that the instability started before the time of splitting at day 6-7.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Gemelos Monocigóticos
/
Proteínas de Unión al ARN
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Repeticiones de Trinucleótidos
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Síndrome del Cromosoma X Frágil
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Proteínas del Tejido Nervioso
Límite:
Child, preschool
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Female
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Humans
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Male
Idioma:
En
Revista:
J Med Genet
Año:
1999
Tipo del documento:
Article
País de afiliación:
Países Bajos