A detailed phenotypic assessment of individuals affected by MFRP-related oculopathy.
OBJECTIVE
To determine the spectrum of mutations and phenotypic variability within patients with mutations in membrane-type frizzled related protein gene (MFRP).


METHODS
Individuals were initially ascertained based on a phenotype similar to that previously published in association with MFRP mutations. Affected patients underwent a full ophthalmic examination (best-corrected visual acuity, slit-lamp examination, applanation tonometry, and fundoscopy), color fundus photography, optical coherence tomography, autofluorescence imaging, and electrophysiology. MFRP was identified by a genome-wide scan in the fourth-largest autozygous region in one consanguineous family. Sanger sequencing of all the exons and intron-exon boundaries of MFRP was undertaken in the affected individuals.


RESULTS
Seven affected individuals from four families were identified as having mutations in MFRP. Patients from two families were homozygous for mutations already previously described (c.1143_1144 insC and c.492 delC), while those from the other two were compound heterozygous for mutations (c.201G>A and c.491_492 insT, and c.492 delC, and c.1622_1625 delTCTG), three of which were novel. There was considerable phenotypic variability within and among families. Autofluorescence imaging revealed the central macula to be relatively well preserved. Foveal cysts and optic nerve head drusen were present in two of the four families. Electrophysiology results showed rod-cone dystrophy with mild to moderate reduction in macular function in all affected members.


CONCLUSIONS
We report three novel MFRP mutations and expand the phenotypic data available on patients with MFRP mutations.
Mukhopadhyay
Rajarshi
R
Department of Genetics, Institute of Ophthalmology, University College London, UK. docrajarshi@doctors.org.uk
Sergouniotis
Panagiotis I
PI
Mackay
Donna S
DS
Day
Alexander C
AC
Wright
Genevieve
G
Devery
Sophie
S
Leroy
Bart P
BP
Robson
Anthony G
AG
Holder
Graham E
GE
Li
Zheng
Z
Webster
Andrew R
AR
D000328:Adult; D001483:Base Sequence; D055724:Electrophysiological Phenomena; D004596:Electroretinography; D005128:Eye Diseases / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D005453:Fluorescence; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010375:Pedigree; D010641:Phenotype; D041623:Tomography, Optical Coherence; D000099274:Frizzled-Related Proteins
D008565:Membrane Proteins; C490110:MFRP protein, human; D000099274:Frizzled-Related Proteins