Microarray-based mutation detection and phenotypic characterization of patients with Leber congenital amaurosis.
OBJECTIVE
To test the efficiency of a microarray chip as a diagnostic tool in a cohort of northwestern European patients with Leber congenital amaurosis (LCA) and to perform a genotype-phenotype analysis in patients in whom pathologic mutations were identified.


METHODS
DNAs from 58 patients with LCA were analyzed using a microarray chip containing previously identified disease-associated sequence variants in six LCA genes. Mutations identified by chip analysis were confirmed by sequence analysis. On identification of one mutation, all protein coding exons of the relevant genes were sequenced. In addition, sequence analysis of the RDH12 gene was performed in 22 patients. Patients with mutations were phenotyped.


RESULTS
Pathogenic mutations were identified in 19 of the 58 patients with LCA (32.8%). Four novel sequence variants were identified. Mutations were most frequently found in CRB1 (15.5%), followed by GUCY2D (10.3%). The p.R768W mutation was found in 8 of 10 GUCY2D alleles, suggesting that it is a founder mutation in the northwest of Europe. In early childhood, patients with AIPL1 or GUCY2D mutations show normal fundi. Those with AIPL1-associated LCA progress to an RP-like fundus before the age of 8, whereas patients with GUCY2D-associated LCA still have relatively normal fundi in their mid-20s. Patients with CRB1 mutations present with distinct fundus abnormalities at birth and consistently show characteristics of RP12. Pathogenic GUCY2D mutations result in the most severe form of LCA.


CONCLUSIONS
Microarray-based mutation detection allowed the identification of 32% of LCA sequence variants and represents an efficient first-pass screening tool. Mutations in CRB1, and to a lesser extent, in GUCY2D, underlie most LCA cases in this cohort. The present study establishes a genotype-phenotype correlation for AIPL1, CRB1, and GUCY2D.
Yzer
Suzanne
S
The Rotterdam Eye Hospital, Rotterdam, The Netherlands.
Leroy
Bart P
BP
De Baere
Elfride
E
de Ravel
Thomy J
TJ
Zonneveld
Marijke N
MN
Voesenek
Krysta
K
Kellner
Ulrich
U
Ciriano
Jose P Martinez
JP
de Faber
Jan-Tjeerd H N
JT
Rohrschneider
Klaus
K
Roepman
Ronald
R
den Hollander
Anneke I
AI
Cruysberg
Johannes R
JR
Meire
Françoise
F
Casteels
Ingele
I
van Moll-Ramirez
Norka G
NG
Allikmets
Rando
R
van den Born
L Ingeborgh
LI
Cremers
Frans P M
FP
D048868:Adaptor Proteins, Signal Transducing; D000429:Alcohol Oxidoreductases / Q000235:genetics; D001766:Blindness / Q000151:congenital* / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D005820:Genetic Testing / Q000379:methods; D005838:Genotype; D006162:Guanylate Cyclase / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010641:Phenotype; D011956:Receptors, Cell Surface / Q000235:genetics*; D012174:Retinitis Pigmentosa / Q000151:congenital / Q000235:genetics; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase
D048868:Adaptor Proteins, Signal Transducing; D000429:Alcohol Oxidoreductases; D002352:Carrier Proteins; D005136:Eye Proteins; D006162:Guanylate Cyclase; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase; C403625:AIPL1 protein, human; C448939:CRB1 protein, human; C110715:guanylate cyclase 1; C489649:RDH12 protein, human