| Neurology |
Early‐onset cerebellar ataxia |
Majority have symptom onset by 10 y of age |
Phenotypically normal clinically |
| Usually, wheelchair bound by early second decade of life |
Cerebellar ataxia may not be the predominant feature and tend to develop later in life if present |
| High incidence oculomotor apraxia |
Most have a mixture of ataxia and/or peripheral neuropathy with extrapyramidal features |
|
Slower progression of neurological disease with delayed loss of ability to walk |
|
Oculomotor apraxia may not always be present, tend to develop at an older age if present |
| Oculocutaneous telangiectasia |
Present |
Present in approximately 60% of patients |
| Pulmonary |
Recurrent sinopulmonary infections |
No significant pulmonary disease |
| AFP |
Elevated |
Elevated |
| Immunological manifestations |
Commonly IgG/IgA immunodeficiency |
No significant immunodeficiency requiring treatment |
| May have elevated levels of IgM |
| Radiosensitivity |
Increased sensitivity to ionizing radiation |
Variable |
Controversial |
| Malignancy |
Increased risk of malignancy, ~25% lifetime risk |
Increased risk of malignancy |
Increased, mainly with regards to risk of breast cancer |
| High incidence of hematological malignancies at a young age |
Later onset of malignancy |
| Adults susceptible to both lymphoid tumors and a variety of solid tumors including breast cancers |
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