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Ophthalmic manifestations of infantile phytanic acid storage disease
Insights
Infantile phytanic acid storage disease presents with vision loss, hearing impairment, and developmental delay. Early diagnosis is crucial as dietary phytanic acid restriction may improve outcomes.
Area of Science:
- Metabolic Disorders
- Ophthalmology
- Genetics
Background:
- Infantile phytanic acid storage disease is a rare genetic disorder.
- It affects multiple organ systems, including the eyes, ears, and nervous system.
Observation:
- Two patients presented with nystagmus, epicanthal folds, esotropia, pigmentary retinopathy, hypotonia, severe hearing impairment, and developmental delay.
- Ophthalmic examination revealed macular and diffuse retinal pigment epithelial defects, vascular attenuation, and pigmentary dispersion.
Findings:
- Both patients had significantly elevated serum phytanic acid levels.
- Electroretinography showed severely subnormal rod- and cone-mediated responses, with inner retinal neuron involvement.
Implications:
- Ophthalmologists may be key in the early recognition of this condition.
- Prompt diagnosis and dietary restriction of phytanic acid may ameliorate disease progression.
Abstract:
Two patients had infantile phytanic acid storage disease. Patient 1 had nystagmus from early infancy, epicanthal folds, esotropia, and a pigmentary retinopathy. The second case had similar manifestations; however, no nystagmus was present. Both patients were hypotonic as infants, had a severe hearing impairment, and were moderately severely developmentally delayed. Serum phytanic acid levels in both cases were clearly elevated. The fundus and fluorescein angiogram showed macular and diffuse retinal pigment epithelial defects, vascular attenuation, and pigmentary dispersion. The electroretinogram demonstrated severely subnormal rod- and cone-mediated responses, with greater involvement evident for responses generated by middle and inner retinal neurons compared with responses mediated by photoreceptors. The ophthalmologist may be the first to recognize the characteristic features of this disorder. Early diagnosis may be important because this disorder may be ameliorated by dietary restriction of phytanic acid.