How is Best Vitelliform Macular Dystrophy diagnosed?

Diagnosis of Best Vitelliform Macular Dystrophy

Best Vitelliform Macular Dystrophy (BVMD), also known as Best disease, is a rare inherited eye disorder that affects the macula, the central part of the retina responsible for sharp central vision. It typically manifests in childhood or early adulthood and can lead to progressive vision loss over time. Diagnosing BVMD involves a combination of clinical evaluation, imaging tests, and genetic testing.

Clinical Evaluation

The first step in diagnosing BVMD is a thorough clinical evaluation by an ophthalmologist or a retina specialist. The doctor will review the patient's medical history, including any family history of eye diseases, and perform a comprehensive eye examination. During the examination, the doctor will assess visual acuity, examine the macula using a specialized instrument called an ophthalmoscope, and look for characteristic signs of BVMD.

Imaging Tests

Imaging tests play a crucial role in the diagnosis of BVMD. One commonly used imaging technique is optical coherence tomography (OCT), which provides high-resolution cross-sectional images of the retina. OCT can reveal the presence of yellowish deposits called vitelliform lesions in the macula, which are a hallmark of BVMD. These lesions can vary in size and shape and may change over time.

Another imaging test that can aid in the diagnosis of BVMD is fundus autofluorescence (FAF). FAF uses a special camera to capture images of the retina's natural fluorescence. In BVMD, FAF can show a characteristic pattern of increased autofluorescence in the macula, corresponding to the vitelliform lesions.

Genetic Testing

Genetic testing is often recommended to confirm the diagnosis of BVMD and identify the specific genetic mutation responsible for the disease. BVMD is primarily caused by mutations in the BEST1 gene, which provides instructions for producing a protein called bestrophin-1. Genetic testing can detect these mutations by analyzing a blood or saliva sample from the patient.

There are several methods of genetic testing, including targeted mutation analysis and gene sequencing. Targeted mutation analysis focuses on known common mutations associated with BVMD, while gene sequencing examines the entire coding region of the BEST1 gene to identify less common or novel mutations. Genetic testing can help confirm the diagnosis, provide information about disease progression and inheritance patterns, and assist in genetic counseling.

Conclusion

Diagnosing Best Vitelliform Macular Dystrophy involves a comprehensive approach that combines clinical evaluation, imaging tests, and genetic testing. The clinical evaluation assesses visual acuity and examines the macula for characteristic signs of BVMD. Imaging tests such as OCT and FAF provide detailed images of the retina, highlighting vitelliform lesions and increased autofluorescence in the macula. Genetic testing confirms the diagnosis and identifies specific mutations in the BEST1 gene. Early and accurate diagnosis of BVMD is crucial for appropriate management and genetic counseling.