Paternal retraction of a fragile X allele to normal size, showing normal function over two generations.
Am J Med Genet A
; 188(1): 304-309, 2022 01.
Article
em En
| MEDLINE
| ID: mdl-34545686
ABSTRACT
The FMR1 premutation (PM55-199 CGG) is associated with fragile X-associated tremor/ataxia syndrome (FXTAS) and when maternally transmitted is at risk of expansion to a hypermethylated full mutation (FM ≥ 200 CGG) that causes fragile X syndrome (FXS). We describe a maternally transmitted PM (77 CGG) that was passed to a son (103 CGG), and to a daughter (220-1822 CGG), who were affected with FXTAS and FXS, respectively. The male with the PM showed low-level mosaicism for normal size of 30 and 37 CGG. This male had two offspring one female mosaic for PM and FM (56, 157, >200 CGG) and another with only a 37 CGG allele detected in multiple tissues, neither with a clinical phenotype. The female with the 37 CGG allele showed normal levels of FMR1 methylation and mRNA and passed this 37 CGG allele to one of her daughters, who was also unaffected. These findings show that post-zygotic paternal retraction can lead to low-level mosaicism for normal size alleles, with these normal alleles being functional when passed over two generations.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteína do X Frágil da Deficiência Intelectual
/
Síndrome do Cromossomo X Frágil
Tipo de estudo:
Diagnostic_studies
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Am J Med Genet A
Assunto da revista:
GENETICA MEDICA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Austrália