Choroideremia is an X-linked ocular disorder that leads to the degeneration of the choriocapillaris, retinal pigment epithelium, and the retinal photoreceptor of the eye due to mutations in the CHM gene, which encodes Rab escort protein-1 (REP1).

Referral information

Mutation screening of the CHM gene is available for male patients with a suspected diagnosis of choroideremia. Mutation scanning of obligate carrier females may also be considered. Please contact the laboratory before referring females for mutation scanning. Pre-symptomatic, carrier testing and prenatal diagnosis are available in families with a previously identified mutation. Confirmation of mutations identified in research laboratories.

Technical information

Mutation scanning by bi-directional Sanger sequencing of all coding exons of the CHM gene. MLPA testing is undertaken in males with normal sequencing results and for female index cases. A proportion of missense changes cannot be classified in which case we may request further family studies.

Price & reporting times

Test Price NHS (£) Price non- NHS (£) TRT (calendar days)
Mutation scanning POA POA 56
Single mutation test POA POA 28
Urgent/Predictive single mutation test POA POA 14
Prenatal diagnosis POA POA 3

Test validation & quality assurance - information for users

In our validation series we identified 25 unique CHM mutations in 36 unrelated patients. The laboratory is UKAS assessed against ISO 15189 standards.

Sample requirements

4ml EDTA blood sample

Referral guidelines

Please see our referral guidelines for more information.

OMIM Number(s) - 303100

Gene(s) - CHM