Abstract
Purpose :
Choroideremia is a bilateral and progressive X-linked chorioretinal degenerative disease caused by mutations in the CHM gene. The mutations result in the absence of the Rab escort protein 1 (REP-1). In this study, we describe the phenotype and genotype of members in two Chinese families affected by choroideremia, and demonstrate the detection of either novel or known mutations of the CHM gene in the family members.
Methods :
We conducted complete ophthalmic examinations in patients from two different Chinese families with members that had choroideremia. Peripheral blood samples were collected from the two families for genetic analyses. The proband subject sample analyses were performed with targeted exome sequencing (TES), including 164 known causative genes of inherited retinal dystrophies (IRD). Sangar sequencing and co-segregation analyses confirmed candidate variants in the family member samples.
Results :
The proband subjects showed severe degeneration in their visual acuity when observed in their ophthalmic examinations, and widespread chorioretinal atrophy was seen using fundoscopy and optical coherence tomography scans. Based on an established filtering strategy of data analyses, along with confirmation by co-segregation, one novel mutation in CHM (c.227_232delinsTGTCATTTCA, p.Gln76Leufs*7) was identified in one family, while a previously reported mutation (c.1584_1587del TGTT, p.V529Hfs*7) was identified in the other family.
Conclusions :
In this study, we reported clinical findings and mutational analyses of two Chinese families with choroideremia. We firstly used the TES approach to successfully identify mutations in CHM from pedigrees with choroideremia, including one novel mutation as well as a known causative mutation. This work not only increases our understanding of the genetic etiology of choroideremia, but may potentially lead to improved genetic counseling for families with choroideremia as well.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.