Choroideremia in a woman with ectodermal dysplasia and complex translocations involving chromosomes X, 1, and 3

Abstract

Background: Choroideremia is an X-linked recessive disorder characterized by vision loss with progressive atrophy of the retinal photoreceptors, retinal pigment epithelium (RPE), and choriocapillaris. Ectodermal dysplasia is a heterogeneous group of disorders characterized by a deficiency of two or more ectodermal derivatives. We report on the phenotypic and genetic characteristics of a 29-year-old woman with both choroideremia and ectodermal dysplasia.

Materials and Methods: Observational case report with physical and ophthalmic examination, fluorescein angiography (FA), visual field testing, electroretinography, and cytogenetic analysis. This study adhered to the tenets of the Declaration of Helsinki and The New York Eye and Ear Infirmary Institutional Review Board guidelines.

Results: Physical and ocular examination revealed hypotrichosis, hypohidrosis, full dentures, meibomian gland hypoplasia, and a decrease in corneal tear film. Visual acuity was hand motions in the right eye and 20/50 in the left eye. Fundus examination and fluorescein angiography were consistent with advanced choroideremia and revealed diffuse bilateral RPE and chorioretinal atrophy with sparing of the fovea. Visual field testing had less than 10-degree central islands in both eyes. Scotopic electroretinogram (ERG) was flat with a small flicker response. Cytogenetic analysis showed a complex translocation involving chromosomes X, 1, and 3: 46,X,t(X;1;3)(q13;q24;q21),inv(9)(p11q13). Selective inactivation of the normal X chromosome was present in blood and skin. Chromosomal analyses of the proband’s family (mother and two brothers) were normal.

Conclusion: An X-autosome chromosomal translocation combined with non-random inactivation of the normal X-chromosome in a woman resulted in the phenotypic findings of choroideremia and ectodermal dysplasia.

KEYWORDS::

• choroideremia
• ectodermal dysplasia
• CHM
• EDA
• chromosomal translocation

ACKNOWLEDGMENTS

Supported in part by the Department of Ophthalmology Research Fund and the Norma Lazar Eye Research Grant of The New York Eye & Ear Infirmary.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.