2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part III: Genetics
Chapter 6: Clinical Genetics
Obtaining a family history and recognizing patterns of inheritance are important for accurate diagnosis and management of hereditary eye diseases.
Although it is important to know whether genes are X-linked, mitochondrial, or autosomal, there is little clinical value in knowing autosomal assignments (1–22), which can be found easily with online databases such as OMIM (Online Mendelian Inheritance in Man).
Chromosomal abnormalities may be evident with cytogenetics. Two important ones for ophthalmologists involve the RB1 gene on chromosome arm 13q and the PAX6 gene on chromosome arm 11p, defects in which result in retinoblastoma and aniridia, respectively.
The phakomatoses are mostly due to recessive oncogenes, with loss of genes causing germline or somatic tumors in a pattern similar to that in retinoblastoma.
Carriers of genetic conditions should be examined for clinical signs of those conditions.
Appropriate referral for genetic counseling and genetic testing is important in most mendelian diseases.
Currently, American Academy of Ophthalmology (AAO) guidelines do not recommend genetic testing for common eye diseases such as age-related macular degeneration (AMD) and primary open-angle glaucoma (POAG) outside the research setting.
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.