Skewed X inactivation in an X linked nystagmus family resulted from a novel, p.R229G, missense mutation in the FRMD7 gene.
Br J Ophthalmol
; 92(1): 135-41, 2008 Jan.
Article
in En
| MEDLINE
| ID: mdl-17962394
ABSTRACT
AIMS:
This study aimed to identify the underlying genetic defect of a large Turkish X linked nystagmus (NYS) family.METHODS:
Both Xp11 and Xq26 loci were tested by linkage analysis. The 12 exons and intron-exon junctions of the FRMD7 gene were screened by direct sequencing. X chromosome inactivation analysis was performed by enzymatic predigestion of DNA with a methylation-sensitive enzyme, followed by PCR of the polymorphic CAG repeat of the androgen receptor gene.RESULTS:
The family contained 162 individuals, among whom 28 had NYS. Linkage analysis confirmed the Xq26 locus. A novel missense c.686C>G mutation, which causes the substitution of a conserved arginine at amino acid position 229 by glycine (p.R229G) in exon 8 of the FRMD7 gene, was observed. This change was not documented in 120 control individuals. The clinical findings in a female who was homozygous for the mutation were not different from those of affected heterozygous females. Skewed X inactivation was remarkable in the affected females of the family.CONCLUSIONS:
A novel p.R229G mutation in the FRMD7 gene causes the NYS phenotype, and skewed X inactivation influences the manifestation of the disease in X linked NYS females.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Eye Diseases, Hereditary
/
Mutation, Missense
/
Nystagmus, Congenital
/
Cytoskeletal Proteins
/
Genetic Diseases, X-Linked
/
Membrane Proteins
Type of study:
Prognostic_studies
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Br J Ophthalmol
Year:
2008
Document type:
Article
Affiliation country:
Turkey