Novel homozygous large deletion including the 5' part of the SPATA7 gene in a consanguineous Israeli Muslim Arab family.

PURPOSE

To identify the genetic defect in a consanguineous Israeli Muslim Arab family with juvenile retinitis pigmentosa (RP).

METHODS

DNA samples were collected from the index patient, her parents, her affected sister, and two non-affected siblings. Genome-wide linkage analysis with 250 K single nucleotide polymorphism (SNP) arrays was performed using DNA from the two affected patients. Owing to consanguinity in the family, we applied homozygosity mapping to identify the disease-causing gene. The candidate gene SPATA7 was screened for mutations with PCR amplifications and direct Sanger sequencing.

RESULTS

Following high-density SNP arrays, we identified several homozygous genomic regions one of which included the SPATA7 gene. Several mutations in SPATA7 have been reported for various forms of retinal dystrophy, including Leber congenital amaurosis (LCA) and juvenile RP. PCR-based sequence content mapping, long-distance PCR amplifications, and subsequent sequencing analysis revealed a homozygous 63.4 kb large deletion that encompasses the 5' part of the SPATA7 gene including exons 1-5. The mutation showed concordant segregation with the phenotype in the family as expected for autosomal recessive mode of inheritance and is consistent with a diagnosis of juvenile RP.

CONCLUSIONS

We report a novel homozygous large deletion in SPATA7 associated with juvenile RP in a consanguineous Israeli Muslim Arab family. This is the first larger deletion mutation reported for SPATA7.