A novel locus for congenital simple microphthalmia family mapping to 17p12-q12

Purpose. To investigate the etiology in a family with autosomal-dominant congenital simple microphthalmia of Chinese origin. Methods. A whole-genome scan was performed by using 382 microsatellite DNA markers after the exclusion of reported candidates linked to microphthalmia. Additional fluorescent markers were genotyped for fine mapping. To find out the novel predisposing gene, 14 candidate genes including CRYBA1 and NCOR1 were selected to screen for the mutation by the PCR direct-sequencing method. Genome-wide single-nucleotide polymorphism (SNP) genotyping was performed to find out the pathogenetic copy number variation, as well. Results. The most statistically significant linkage results were obtained at D17S1824 (maximum LOD score, 4.97, at recombination fraction 0.00). Haplotype analyses supported the location of the disease-causing gene to a 21.57-cM interval between loci D17S900 and D17S1872 of chromosome 17, region p12-q12. However, no mutation or CNV (copy number variation) was identified to be responsible for the microphthalmia phenotype of this pedigree. Conclusions. A novel suggestive linkage locus for congenital microphthalmia was detected in a Chinese family. This linkage region provides a target for susceptibility gene identification.