Comprehensive mutational screening in a cohort of Danish families with hereditary congenital cataract.
OBJECTIVE
Identification of the causal mutations in 28 unrelated families and individuals with hereditary congenital cataract identified from a national Danish register of hereditary eye diseases. Seven families have been published previously, and the data of the remaining 21 families are presented together with an overview of the results in all families.


METHODS
A combined screening approach of linkage analysis and sequencing of 17 cataract genes were applied to mutation analyses of total 28 families.


RESULTS
The study revealed a disease locus in seven of eight families that were amenable to linkage analysis. All loci represented known genes, and subsequent sequencing identified the mutations. Mutations were found in eight genes, among them crystallins (36%), connexins (22%), and the transcription factors HSF4 and MAF (15%). One family carried a complex CRYBB2 allele of three DNA variants, and a gene conversion is the most likely mutational event causing this variant. Ten families had microcornea cataract, and a mutation was identified in eight of those. Most families displayed mixed phenotypes with nuclear, lamellar, and polar opacities and no apparent genotype-phenotype correlation emerged.


CONCLUSIONS
In total, 28 families were analyzed, and mutations were identified in 20 (71%) of them. Despite considerable locus heterogeneity, a high mutation identification rate was achieved by sequencing a limited number of major cataract genes. Provided these results are representative of Western European populations, the applied sequencing strategy seems to be suitable for the exploration of the large group of isolated cataracts with unknown etiology.
Hansen
Lars
L
Wilhelm Johannsen Centre for Functional Genome Research, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
Mikkelsen
Annemette
A
Nürnberg
Peter
P
Nürnberg
Gudrun
G
Anjum
Iram
I
Eiberg
Hans
H
Rosenberg
Thomas
T
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002386:Cataract / Q000151:congenital* / Q000235:genetics*; D002675:Child, Preschool; D017630:Connexins / Q000235:genetics; D003315:Cornea / Q000002:abnormalities; D003459:Crystallins / Q000235:genetics*; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics; D003718:Denmark; D015785:Eye Diseases, Hereditary / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage; D005838:Genotype; D000076249:Heat Shock Transcription Factors; D006801:Humans; D008126:Lod Score; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D051257:Proto-Oncogene Proteins c-maf / Q000235:genetics; D012042:Registries; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics; D044465:White People / Q000235:genetics; D038206:beta-Crystallin B Chain / Q000235:genetics; D038222:gamma-Crystallins
C511246:CRYAA protein, human; C103908:CRYBB3 protein, human; C504903:CRYGD protein, human; D017630:Connexins; D003459:Crystallins; D004268:DNA-Binding Proteins; C102948:HSF4 protein, human; D000076249:Heat Shock Transcription Factors; C495607:MAF protein, human; D051257:Proto-Oncogene Proteins c-maf; D014157:Transcription Factors; D038206:beta-Crystallin B Chain; C113634:beta-crystallin B2; D038222:gamma-Crystallins