Skewed X inactivation in an X linked nystagmus family resulted from a novel, p.R229G, missense mutation in the FRMD7 gene
Author(s)
Date
2008Source Title
British Journal of Ophthalmology
Print ISSN
0007-1161
Publisher
BMJ Group
Volume
92
Issue
1
Pages
135 - 141
Language
English
Type
ArticleItem Usage Stats
388
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317
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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.
Keywords
Amino acidArginine
Glycine
Cytoskeleton protein
FRMD7 protein, human
Membrane protein
Unclassified drug
Article
Congenital nystagmus
DNA methylation
Exon
Family
Female
Gene activation
Gene locus
Gene mutation
Gene sequence
Genetic linkage
Heterozygosity
Homozygosity
Human
Intron
Major clinical study
Male
Missense mutation
Phenotype
Polymerase chain reaction
Priority journal
Substitution reaction
X chromosome
X chromosome linked disorder
Adult
Aged
Congenital nystagmus
Eye disease
Genetics
Methodology
Middle aged
Non insulin dependent diabetes mellitus
Nucleotide sequence
Obesity
Pedigree
X chromosome inactivation
X chromosome linked disorder
Base Sequence
Cytoskeletal Proteins
Diabetes Mellitus, Type 2
DNA Mutational Analysis
Eye Diseases, Hereditary
Female
Genetic Diseases, X-Linked
Humans
Linkage (Genetics)
Male
Membrane Proteins
Middle Aged
Mutation, Missense
Nystagmus, Congenital
Obesity
Pedigree
X Chromosome Inactivation
Permalink
http://hdl.handle.net/11693/23235Published Version (Please cite this version)
http://dx.doi.org/10.1136/bjo.2007.128157Collections
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