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Description
A man in early adolescence, born out of consanguineous marriage, presented with progressive gait unsteadiness and recurrent sinopulmonary and soft tissue infections for 5 years. On examination, he had bulbar conjunctival telangiectasia (figure 1), oculomotor apraxia, bilateral cerebellar signs and bilateral, horizontal, coarse, gaze evoked nystagmus. MRI of the brain revealed diffuse cerebellar atrophy. Laboratory investigations revealed elevated serum alfa-fetoprotein with a decreased serum IgA level. The patient was diagnosed with ataxia telangiectasia (A-T), which was confirmed with whole genome sequencing.
A-T is an autosomal recessive, inherited, neurodegenerative disorder characterised by progressive cerebellar degeneration, associated with immunodeficiency and increased risk for malignancy.1 2 A-T was first described by Elena Boder and Robert P. Sedgwick in 1957 as a familial syndrome of cerebellar ataxia, frequent pulmonary infections and oculocutaneous telangiectasia. Patients with A-T have a significantly increased incidence of cancers (leukaemias, lymphoid malignancies and solid tumours, such as oesophageal, gastric, liver and breast carcinomas).1 Clinicians must be aware of the potential for malignancy, and particularly haematological malignancy, in these patients. Conjunctival telangiectasia can be seen in some inherited systemic syndromes such as A-T, hereditary haemorrhagic telangiectasia, Fabry’s disease, Bloom syndrome, Alport syndrome and may also be associated with chronic ocular surface disorders such as ocular rosacea.3 Telangiectasia in A-T is noted primarily on interpalpebral, bulbar conjunctiva over the exposed portion of sclera and they may appear much later than neurological symptoms.4 Adults with milder forms of the disease (variant A-T) often do not have ocular telangiectasia.5 Therefore, their absence does not exclude the diagnosis of A-T. They do not bleed usually and they are sometimes misdiagnosed as chronic conjunctivitis. Abnormal eye movements such as oculomotor apraxia, nystagmus, accommodation abnormalities and hypometric saccades may be associated with A-T. Mutation of the ATM gene responsible for coordinating the signalling pathways in response to genotoxicity leads to A-T.6 The importance of vigilant ophthalmic examination in the diagnosis of hereditary neurodegenerative disorders is hereby emphasised.
Learning points
Ataxia telangiectasia (A-T) is a childhood-onset, autosomal recessive, cerebellar ataxia with characteristic ocular findings that emphasise the importance of ocular examination in/when evaluating patients with ataxia.
Several other neurological disorders may be associated with conjunctival telangiectasia and so may be confused with A-T. Differentiation of these disorders from A-T may be done by careful clinical examination and specific laboratory tests, including gene sequencing.
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Footnotes
Contributors The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content: UC, AC and SD contributed to conception, initial drafting of manuscript, patient management, critical revision of content and final approval of manuscript. All authors are in agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The following authors gave final approval of the manuscript: UC, AC and SD.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.