A novel mutation in the dominantly inherited TOPORS gene supports haploinsufficiency as the mechanism of retinitis pigmentosa.

Inherited retinal degenerations are a major cause of untreatable blindness in the younger age group. Recent advances in gene therapy using adeno-associated viral (AAV) vectors have raised the possibility of slowing or stopping retinal degenerations with gene replacement in cases of gene deficiency. In this report, we present a family with autosomal dominant retinitis pigmentosa. A screen for common ADRP genes was performed with 105 genes targeted. Next generation sequencing was used to identify the mutation which was next confirmed by bidirectional Sanger sequencing. A novel mutation of the TOPORS gene was identified, c.2539C>T p.(Arg847Ter), resulting in a premature termination codon and suggesting haploinsufficiency as the pathological mechanism. Since the cDNA encoding TOPORS is 3,135 nucleotides (within the coding capacity of AAV vectors) and haploinsufficiency is a mechanism relating to inadequate gene expression, gene replacement therapy may be an option for patients with this condition.

Citation

Marta Latasiewicz, Anna Paola Salvetti, Robert E MacLaren. A novel mutation in the dominantly inherited TOPORS gene supports haploinsufficiency as the mechanism of retinitis pigmentosa. Ophthalmic genetics. 2017 Dec;38(6):562-566

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PMID: 28453362

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