Heredofamilial neurocutaneous progressive syndrome
characterized by cerebellar ataxia (early childhood), oculocutaneous
telangiectasia (adolescence), and impairment of the immune system. Recurrent
infections of the lung (pulmonary restrictive disease) and sinuses.
Ocular telangiectasias in a patient with ataxia telangiectasia.
Similar telangiectases in Louis-Bar syndrome can also be found on the ear.
Ataxia Telangiectasia Syndrome.
Described by Denise Louis-Bar, a Belgian neuropathologist,
Autosomal recessive. The ataxia telangiectasia
(AT) gene has been localized to chromosome 11q23.
Ataxia telangiectasia is a syndrome with
multiorgan involvement. Pathophysiology cannot be explained by a single
cellular mechanism. Neurologic: Cerebellar dysfunction, progressive neurologic
deterioration, developmental delay; mucocutaneous: telangiectasia on conjunctiva and
exposed areas; endocrine: glucose intolerance, hypogonadism.
Based on clinical features. Immunodeficiency as
evidenced by low or absent IgA and IgE and atypical IgM. Slight elevation of
liver enzymes in 50% of patients. May have raised α-fetoprotein.
Glucose intolerance and hypogonadism particularly seen in females. Marked
progressive cerebellar atrophy usually is demonstrated early by CT scan or
MRI and characteristically defined as enlarged cerebellar sulci and cisterns
and fourth ventricle.
Initial presentation usually is neurologic as
evidenced by problems with development of walking, oculomotor abnormalities,
and progressive neurologic disability. Risk of recurrent aspiration of oral
secretions. In addition to telangiectasia, vitiligo, café-au-lait spots,
and premature graying may be present. Absence of secondary sexual
characteristics in females. Elevated liver enzymes associated with fatty
infiltration of the liver. Ataxia telangiectasia patients are at increased
risk for developing malignancies, particularly lymphoma and leukemia in
children and gastric carcinoma in adults. Chronic respiratory infections and
bronchiectasis, unresponsive to antibiotics, are frequently the ultimate
cause of death. Unusual to survive beyond the third decade.
Neurologic evaluation, particularly
cerebellar and bulbar function. Evaluate pulmonary and cardiac function in
light of chronic lung disease. Objective evaluation of respiratory system
may be difficult because of neurologic disease. Hematologic evaluation
should look for malignancies that may result in pancytopenia, requiring
blood or platelet transfusions preoperatively. Evaluation of hepatic
function, glucose homeostasis, and coagulation profile.
Patient cooperation may be limited
because of mental deficiency. Ventilation/oxygenation may be challenging
because of chronic lung disease. May need postoperative ventilation.
Increased risk of aspiration because of neurologic disease. Although there
are no known direct cardiac anomalies, the presence of chronic lung disease
and the potential effect of increased pulmonary vascular resistance on
cardiac function must be evaluated.
Drugs that depend on hepatic
metabolism should be used with care in the presence of hepatic dysfunction.
Use muscle relaxants judiciously in presence of progressive neurologic
Jones KL: Ataxia telangiectasia syndrome, in Lyons K (ed): ...