= autosomal recessive disorder characterized by telangiectasias of skin + eye, cerebellar ataxia, sinus + pulmonary infections, immunodeficiencies, propensity to develop malignancies

Incidence: 1÷40,000 livebirths

Path: neuronal degradation + atrophy of cerebellar cortex (? from vascular anomalies)

• cerebellar ataxia at beginning of walking age
• progressive neurologic deterioration
• oculomotor abnormalities, dysarthric speech, choreoathetosis, myoclonic jerks
• mucocutaneous telangiectasias: bulbar conjunctiva, ears, face, neck, palate, dorsum of hands, antecubital + popliteal fossa
• recurrent bacterial + viral sinopulmonary infections
• cerebellar cortical atrophy: diminished cerebellar size, dilatation of 4^th ventricle, increased cerebellar sulcal prominence
• cerebral hemorrhage ← rupture of telangiectatic vessels
• cerebral infarct ← emboli shunted through vascular malformations in lung

Cx:

1. Bronchiectasis + pulmonary failure (most common cause of death)
2. Malignancies (10–15%): lymphoma, leukemia, epithelial malignancies