|Medical Ophthalmology: Case nine|
This 18 year-old gird had been wheel-chair bound since 10 years of age. She also had problem with her balance. Recently, she developed problem with her vision.
a. What do the pictures show?Figure 1 shows pes cavus and figure 2 shows Harrington's rod inserted in the thoracic spine in an attempt to correct a scoliosis.b. What is the most likely diagnosis?Friedrich's ataxia.
The condition is one of the hereditary spinocerebellar degenerations. It is usually inherited in an autosomal recessive fashion. The gene abnormality is located on the long arm of chromosome 9. It has the following features:
The condition is progressive and most sufferers are wheel-chair bound by 15 years of age. Death due to pulmonary infection (caused by severe scoliosis) or cardiomyopathy occurs in the fourth or fifth decade of life.
- cerebellar dysfunction with ataxia, nystagmus and dysarthria
- absent knee and ankle jerks but the plantar responses are extensor
- loss of joint position and vibratory sensation
- diabetes mellitus
- poor vision due to optic atrophy
c. What ocular signs may be present?The following ocular signs may occur with Friedrich's ataxia:
- nystagmus from cerebellar involvement
- optic atrophy
- retinal pigmentary changes which may resemble retinitis pigmentosa
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