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Editor,—Aicardi syndrome1 is a congenital disorder characterised by severe epilepsy, agenesis of the corpus callosum, typical chorioretinal lacunae, and learning disabilities. Normally it carries a poor prognosis. We present a case in which these symptoms have been found in a 49 year old woman, suggesting a “forme fruste” of the disorder.
A 49 year old woman previously thought to have cerebral and retinal toxoplasmosis was referred because of visual deterioration, poor balance, and obvious visual field restriction.
On examination her corrected visual acuities were right 0.2 (6/9.5) and left 0.8 (6/38) (Bailey-Lovie chart). The fundi of both eyes showed large chorioretinal defects adjacent to the discs and smaller rounded pale yellow “punched out” chorioretinal lacunae scattered around the posterior pole, as is typical in Aicardi syndrome. Her discs were hypoplastic with marginal pigmentation nasally. She also had three pigmented lesions surrounding the left fovea typical of healed disciform scars(Fig 1).
A computed tomographic scan was performed which showed dysgenesis of the corpus callosum. There was no intracranial calcification as seen in cerebral toxoplasmosis (Fig 2).
The youngest of five children of a 39 year old mother, she was seen in the school clinic aged 4 when she was noted to have choroidal lesions. A plain skull x ray was suggestive of hydrocephalus. She was mildly intellectually impaired with seizures manifesting as left sided clonic movements, followed by loss of awareness. At 9 years old she could print her name and recognise letters but was unable to read. Her seizures were helped by a combination of phenobarbitone and primidone. At 14 her seizures, learning disability, and eye changes were thought to be due to cerebral and ocular toxoplasmosis. The dye test was weakly positive at 1:8. At the age of 20 her corrected visual acuities were 6/9 right and 6/12 left Snellen, with an alternating left divergent squint and a slight left ptosis. She had moderate myopic astigmatism which was more marked in the right eye. Drawings of the fundi at this time show chorioretinal lacunae adjacent to the disc, but not extending over the macular area.
She was examined at the age of 44 when she had developed disciform changes at the left macula following a drop in VA 2 years earlier. She is living in the community and is virtually seizure free on carbamazepine 800 mg twice daily. G banding studies show an apparently normal 46XX karyotype. Radiology reveals no evidence of costovertebral abnormality.
Aicardi syndrome is thought to be an X linked dominant disorder.2 Females are exclusively affected, the disorder being lethal in males. There is heterogeneity of clinical severity. Most patients have severe learning disability, intractable epilepsy, agenesis of the corpus callosum, and reduced life expectancy. However, recently a 10 year old girl has been described with a mild form of the disorder.3
Previous necropsy studies on the chorioretinal lacunae have shown focal thinning and atrophy of the retinal pigment epithelium and choroid.4 We suggest that the pigmented paramacular lesions seen in our case may have been caused by choroidal new vessels penetrating a break in Bruch’s membrane, as has been described in choroideraemia, Best’s disease, and rubella retinopathy.5
The fundal appearances are atypical of chorioretinitis due to toxoplasmosis and there is no intracranial calcification to support that diagnosis.
Our case suggests that there may be a wide spectrum of Aicardi syndrome. She is not severely mentally disabled and her epilepsy has been well controlled. However, she does have the typical chorioretinal lacunae present from childhood, and dysgenesis of the corpus callosum. The striking feature is that she was diagnosed in middle age, providing further evidence that a mild form of the disease does exist.3