Clinical Trial Summary
This study will explore the causes and eye problems of X-linked juvenile retinoschisis
(XLRS), an inherited disease that causes vision loss primarily in young males. The vision
loss, which worsens over time, is a result of schisis, or splitting, of the layers of the
retina (tissue that lines the back of the eye). A better understanding of why and how XLRS
develops might lead to improved treatments.
Patients 9 months of age and older with XLRS and females who are suspected carriers of the
gene responsible for the disease (such as the mother of the patient) may be eligible for this
study. Other family members of patients also may be enrolled.
Patients will undergo the following tests and procedures:
- Personal and family medical history to review past and current medical conditions and
treatments, particularly regarding eye disease, and to construct a family tree.
- Eye examination to assess visual acuity (eye chart test) and examine pupils, lens,
retina, and eye movements. The pupils will be dilated with drops for this examination.
- Photography of the retina to help evaluate the status of the retina.
- Specialized eye tests to evaluate color vision, field of vision, and ability to see in
the dark.
- Electroretinogram (ERG) to examine what happens to the eyes after a flash of bright
light. For this test, the patient sits in a dark room for 30 minutes with his or her
eyes patched. Then, a small silver disk electrode is taped to the forehead, the eye
patches are removed, the surface of the eye is numbed with eye drops and contact lenses
are placed on the eyes. The patient looks inside a large empty bowl and then a light
flashes, first in the dark and then with a light turned on inside the bowl. The contact
lenses sense small electrical signals generated by the retina when the light flashes.
- Blood test to examine DNA for genetic study of XLRS.
Family members will provide a blood sample for genetic study.
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Objectives:
The overall goal of this protocol is to better understand the etiology of XLRS disease to
facilitate further research to identify a potential treatment for the disease. The specific
primary objectives of this study are to:
1. Investigate the relationship between genotype and phenotype in X-Linked Retinoschisis by
correlating four phenotype severity classes with two classes of genotypes. This is the
first step in developing a comprehensive genotypephenotype
correlation.
2. Characterize the anatomical and functional characteristics of retinoschisis to refine
the phenotype scale and investigate and characterize specific XLRS1 mutations to
generate a well-documented genotype-phenotype correlation map.
With the opportunity to study the genotypes and phenotypes of many affected males and the
genotype of family members, a secondary objective of this study will be to develop a detailed
pedigree for affected families. This information may be used to develop preliminary risk
estimates for potential carrier females.
Study Population:
Up to 500 participants may enroll in this study. A minimum of 150 of participants are
expected to be males diagnosed with X-Linked Retinoschisis. Participants may be recruited
from the NIH and also from participating off-site locations. The quality of the genetic
observation is directly proportional to the number of affected individuals and
genetically-different families enrolled.
Design:
This natural history, multi-center, registry study to enroll males diagnosed with X-Linked
Retinoschisis and the family members of affected individuals. Onsite affected males will
undergo clinical examination and have their blood drawn for genotyping. Onsite unaffected
participants will undergo eye examinations. Blood may also be drawn from the onsite
unaffected participants but this is not required. Sites outside of NIH are participating as
referral centers to accumulate the cohort. Offsite affected male participants will forward a
blood sample and records from previous eye examinations to the NEI for review and analysis.
Offsite unaffected participants will forward records from previous eye examinations and may
provide a blood sample although this is not required.
Outcome Measures:
The primary outcome is the categorization of the proband s genotype and phenotype and
determination of the relationship between the two.
