Neurology

Answer 4 AFP and CEA. This child has the classic triad of ataxia, telangiectasia, and frequent sinopulmonary infections, which suggests a diagnosis of ataxia-telangiectasia (AT).5 AT is an autosomal recessive disorder affecting the ATM gene on chromosome 11q22-23, which is a gene involved in cell-cycle progression and DNA repair. Ataxia begins proximally and spreads distally, and choreoathetosis is frequent. Telangiectasias appear between age 2 and 10 years, and mild mental retardation occurs in 1 in 3 persons. There is an increased tendency to develop malignancies, especially lymphomas and leukemias. The immune system is also impaired, accounting for recurrent infections. AFP is often elevated, CEA may be elevated, and IgG (especially subclasses 2 and 4), IgA, and IgE are depressed. Together these tests have up to 90% sensitivity. Specific testing for the ATM gene is also available. Brain MRI may show cerebellar atrophy. Management of AT includes aggressive treatment of infections and avoiding radiation, including chest radiography and sunbathing. In the past, early death was most commonly the result of infection but is now caused by malignancies. Heterozygotes are also at risk for malignancy, especially breast cancer. Urine for catecholamines is a test for neuroblastoma (opsoclonus-myoclonus) and pheochromocytoma. REFERENCE 5. Perlman S, Becker-Catania S, Gatti RA. Ataxia-telangiectasia: diagnosis and treatment. Semin Pediatr Neurol 2003;10: 173-82. Click here to return to the questions

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