Spectrum and frequency of FZD4 mutations in familial exudative vitreoretinopathy.
OBJECTIVE
Mutations in the frizzled-4 gene (FZD4) have recently been associated with autosomal dominant familial exudative vitreoretinopathy (FEVR) in families linking to the EVR1 locus on the long arm of chromosome 11. The purpose of this study was to screen FZD4 in a panel of 40 patients with FEVR to identify the types and location of mutations and to calculate what proportion of this heterogeneous condition is attributable to FZD4 mutations.


METHODS
PCR products were generated from genomic DNA with primers designed to amplify the coding sequence of FZD4. The PCR products were screened for mutations by single-strand conformational polymorphism-heteroduplex analysis (SSCP-HA) and by direct sequencing.


RESULTS
In total, eight mutations were identified, seven of which were novel. Three were deletions (c957delG, c1498delA, and c1501-1502delCT), one was a nonsense mutation (Q505X), and four were missense mutations (G36D, M105T, M157V, and S497F).


CONCLUSIONS
Eight mutations have been identified in the FZD4 gene in a cohort of 40 unrelated patients with FEVR. This result indicates that FZD4 mutations are responsible for only 20% of FEVR index cases and suggests that the other FEVR loci may account for more cases than previously anticipated.
Toomes
Carmel
C
Molecular Medicine Unit, University of Leeds, United Kingdom. c.toomes@leeds.ac.uk
Bottomley
Helen M
HM
Scott
Sheila
S
Mackey
David A
DA
Craig
Jamie E
JE
Appukuttan
Binoy
B
Stout
J Timothy
JT
Flaxel
Christina J
CJ
Zhang
Kang
K
Black
Graeme C M
GC
Fryer
Alan
A
Downey
Louise M
LM
Inglehearn
Chris F
CF
D000328:Adult; D000595:Amino Acid Sequence; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics; D004252:DNA Mutational Analysis; D017931:DNA Primers / Q000737:chemistry; D005122:Exudates and Transudates; D005260:Female; D051157:Frizzled Receptors; D005787:Gene Frequency; D020180:Heteroduplex Analysis; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011506:Proteins / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000235:genetics*; D043562:Receptors, G-Protein-Coupled; D018630:Vitreoretinopathy, Proliferative / Q000235:genetics*
D017931:DNA Primers; C402930:FZD4 protein, human; D051157:Frizzled Receptors; D011506:Proteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled