What are the symptoms of A-T?
An affected child usually begins to show signs of clumsiness shortly after learning to walk, around one year ot eighteen months of age. This is followed slowly by increased loss of balance, slurring of words, and uncoordinated eye movements. Small, dilated blood bessels appear over the whites of the eyes, bridge of the nose, or ears, or elsewhere (these are called telangiectasias); this is not seen in ther kinds of early onset ataxias. Repeated upper respiratory infections of the sinuses and lungs occur due to an underlying immunodeficiency. A neurologist can document that the loss of balance is due to loss of cerebellar function within the brain. Kids with A-T will usually need to use a wheelchair by age 10. Occasionnally, cancer is the first symptom to appear, usually as a lymphoma or leukemia. This is a particularly dangerous situation because cancer in A-T patients must be treated differently - with a different protocol. Later in life, muscles of the hands and feet become spastic. A persistant cough can signal a swallowing/feeding issue or the onset of chronic lung failure.
Symptoms
A-T affects many parts of the body:
- It impairs certain areas of the brain including the cerebellum, causing difficulty with movement and coordination.
- It weakens the immune system causing a predisposition to infection (affect about 70% of children with A-T).
- It prevents repair of broken DNA, increasing the risk of cancer.
Children are born seemingly healthy. but as time moves on, they become symptomatic. Often, the children are diagnosed as having Cerebral Palsy until it becomes clear that symptoms with regard to balance issues are not static. Symptoms most often first apprear in early childhood when children begin to walk. Though they usually start walking at a normal age, they begin to lose the ability to control muscle movement. They wobble or sway when walking, standing still or sitting, and may appear almost as if they are drunk. Over time, children lose their independence. A wheelchair is needed usually by the age of 10, if not befoire. They develop slurred or distorted speech, and swalloging problems. Some have an increased number of respiratorty tract infections since their immune system is aslo affected, making them more prone to chest infections and predisposed to cancer. Because not all children develop in the same manner or at the same rate, it may be some years before A-T is properly diagnosed. Most children with A-T have stable neurologic symptoms for the first 4-5 years of life, but begin to show increasing problems in early school years. Intellectually, the children remain entirely capable and so over time they effectively become trapped inside their deteriorating body.
There is substantial variability in the severity of features of A-T between affected individuals, and at different ages. The following symptoms or problems are either common or important features of A-T:
- Ataxia (difficulty with control of movement) that is apparent early but worsens in school to pre-teen years;
- Oculomotor apraxia (difficulty with coordination of head and eye movement when shifting gaze from one place to the next);
- Involuntary movements;
- Telangiectasia (dilated blood vessels) over the white (sclera) of the eyes, making them appear bloodshot. These are not apparent in infancy and may first appear at age 5-8 years. Telangiectasia may also appear on sun-exposed areas of skin;
- Problems with infections, especially of the ears, sinuses and lungs;
- Increased incidence of cancer (primarily, but not exclusively, lymphomas and leukemia);
- Slowed rate of growth (weight and/or height);
- Drooling particularly in young children when they are tired or concentrating on activities;
- Dysarthria (slurred, slow or distorted speech sounds);
- Choreothetosis (the occurence of involuntary movements in a combination of chorea (irregular migrating contractions) and athetosis (twisting and writhing);
- Myoclonus (a brief, involuntary twitching of a muscle (jerky movements);
- Diabetes in adolescence or later;
- Premature changes in hair and skin.
Many children are initially misdiagnosed as having ataxic cerebral palsy. The diagnosis of A-T may not be made until the preschool years when the neurologic symptoms of impaired gait, hand coordination, speech and eye movement appear or worsen, and the telangiectasia first appear. Because A-T is so rare, doctors may not be familiar with the symptoms, or methods of making a diagnosis. The late appearance of telangiectasia may be a barrier to the diagnosis. It may take some time before doctors consider A-T as a possibility because of the early stability of symptoms and signs.
All teenagers with classic A-T need help with dressing, eating, washing, and using the toilet. Because swallowing is not well coordinated, eating should be slow and deliberate to avoid aspirating food. Muscle strenght is normal at first but wanes with disuse, especially in the legs. Contractures in the fingers and toes are common in older individuals but may be minimized by rigorous exercice.
Intelligence is typically normal; however, learning difficulties are common. Slow motor and verbal responses make it difficult for individuals to complet timed IQ tests. Many American and British individuals with classic A-T have finished high school with good grades, some have finished college or university.
Next... How is the diagnosis of A-T made?