A novel large multi-gene deletion in syndromic choroideremia

Caused by mutation or deletion of the CHM gene, choroideremia is a rare X-linked recessive chorioretinal dystrophy characterized by progressive degeneration of the retinal pigment epithelium, photoreceptors, and the choriocapillaris. There are few published reports of choroideremia associated with complex syndromic phenotypes due to large or contiguous gene deletions.

Case report and review of literature.

We present a case of a 46-year-old male with a prior clinical diagnosis of syndromic retinitis pigmentosa, who was found to have syndromic choroideremia associated with a novel multi-gene deletion of 13.5 megabase pairs. This deletion encompassing 18 genes is one of the largest deletions reported in the literature. A total of 18 male cases of choroideremia associated with confirmed large or contiguous gene deletions have been published to date. Previously reported deletions range in size from 4 to 15 megabase pairs, and observed phenotypes include cleft lip and palate, ptosis, obesity, metabolic diseases, developmental delay, and hearing loss.

The contribution of our case aims to expand our understanding of Xq21 deletions and prompts further investigation of genes found in this locus. Furthermore, it highlights the importance of including syndromic choroideremia on the differential diagnosis in the workup of other syndromic retinopathies, particularly those that feature obesity, hearing loss, or intellectual disability.