Carriage of One or Two FMR1 Premutation Alleles Seems to Have No Effect on Illness Severity in a FXTAS Female with an Autozygous FMR1 Premutation Allele.
Cerebellum
; 15(5): 570-7, 2016 10.
Article
in En
| MEDLINE
| ID: mdl-27315125
ABSTRACT
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that occurs in FMR1 premutation carriers. The prevalence of FMR1 premutation carriers in the general population is relatively high, and although rare, a premutation in both X chromosomes may occur in females inheriting a premutation allele from each of both parent carriers. Here, we report the first female with an autozygous (homozygous by descendent) FMR1 premutation allele, who fulfills neurological and radiological FXTAS findings/criteria. Molecular characterization included CGG repeat length, AGG interruption pattern, FMR1 messenger RNA (mRNA), fragile X mental retardation protein (FMRP) level quantification, and single-nucleotide polymorphism (SNP) microarray. Neuroradiological assessment of 3-T magnetic resonance imaging and neurological and cognitive/neuropsychological evaluations were performed. Neurological and neuroradiological examination of the female with the same FMR1 allele in the premutation range (77 CGGs) demonstrated FXTAS features. Further familial evaluation showed a similar neuropsychiatric profile, with impairments in cognitive flexibility and visuospatial function, mainly. A unique family with an autozygous FMR1 premutation female is presented. Neurological/cognitive and neuroradiological examinations revealed FXTAS-specific findings in the female with the autozygous FMR1 premutation allele. The consistent molecular and cognitive/psychiatric phenotype in family members suggests that carrying one or two FMR1 premutation alleles has no effect on illness severity.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ataxia
/
Tremor
/
Gene Dosage
/
Fragile X Mental Retardation Protein
/
Fragile X Syndrome
Type of study:
Risk_factors_studies
Limits:
Adult
/
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Cerebellum
Journal subject:
CEREBRO
Year:
2016
Type:
Article
Affiliation country:
Spain