Ann Lab Med.  2017 Sep;37(5):438-442. 10.3343/alm.2017.37.5.438.

Identification of Pathogenic Variants in the CHM Gene in Two Korean Patients With Choroideremia

• Bae K
• Song JS
• Lee C
• Kim NK
• Park WY
• Kim BJ
• Ki CS
• Kim SJ

• KMID: 2383921
• DOI: http://doi.org/10.3343/alm.2017.37.5.438

Abstract

Choroideremia is a rare X-linked disorder causing progressive chorioretinal atrophy. Affected patients develop night blindness with progressive peripheral vision loss and eventual blindness. Herein, we report two Korean families with choroideremia. Multimodal imaging studies showed that the probands had progressive loss of visual field with characteristic chorioretinal atrophy, while electroretinography demonstrated nearly extinguished cone and rod responses compatible with choroideremia. Sanger sequencing of all coding exons and flanking intronic regions of the CHM gene revealed a novel small deletion at a splice site (c.184_189+3delTACCAGGTA) in one patient and a deletion of the entire exon 9 in the other. This is the first report on a molecular genetic diagnosis of choroideremia in Korean individuals. Molecular diagnosis of choroideremia should be widely adopted for proper diagnosis and the development of new treatment modalities including gene therapy.

Keyword

Choroideremia; CHM; Inherited retinal degeneration

MeSH Terms

Atrophy
Blindness
Choroideremia*
Clinical Coding
Diagnosis
Electroretinography
Exons
Genetic Therapy
Humans
Introns
Molecular Biology
Multimodal Imaging
Night Blindness
Visual Fields

Figure

• 

  Fig. 1 Ocular phenotypes exhibited by the probands (indicated by arrows) and the pedigrees of family A (A-D) and family B (E-H). (A, E) Fundus photograph. (B, F) Spectral-domain optical coherence tomography. (C, G) Fundus autofluorescence photograph. (D, H) Family pedigree.

• 

  Fig. 2 CHM variants identified in the probands of family A and family B. (A) Chromatogram of c.184_189+3delTACCAGGTA (p.Tyr62_Gln-63del) detected in the proband of family A. (B) PCR products of exon 9. Exon 9 deletion was detected in the proband of family B.

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