Ataxia-Telangiectasia is divided into 2 types
* Inherited
* Acquired/degenerative
Sporadic ataxia means there is no family history of A-T
Acquired ataxia is caused by degenerative diseases (eg, cerebellar variant of multiple systems atrophy (type C)), deficiency states (eg, vitamin B12, vitamin E), infections (eg, HIV, sporadic Creutzfeldt-Jakob disease, progressive multifocal leukoencephalopathy).
Inherited ataxia can be caused by X-linked, autosomal or mitochondrial inheritance. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6585307/. Missing or empty |title= (help)</ref>

There is no established system for the classification of [disease name].

OR

[Disease name] may be classified according to [classification method] into [number] subtypes/groups: [group1], [group2], [group3], and [group4].

OR

[Disease name] may be classified into [large number > 6] subtypes based on [classification method 1], [classification method 2], and [classification method 3]. [Disease name] may be classified into several subtypes based on [classification method 1], [classification method 2], and [classification method 3].

OR

Based on the duration of symptoms, [disease name] may be classified as either acute or chronic.

OR

If the staging system involves specific and characteristic findings and features: According to the [staging system + reference], there are [number] stages of [malignancy name] based on the [finding1], [finding2], and [finding3]. Each stage is assigned a [letter/number1] and a [letter/number2] that designate the [feature1] and [feature2].

OR

The staging of [malignancy name] is based on the [staging system].

OR

There is no established system for the staging of [malignancy name].

There is no established system for the classification of [disease name].

OR

[Disease name] may be classified according to [classification method] into [number] subtypes/groups:

• [Group1]
• [Group2]
• [Group3]
• [Group4]

OR

[Disease name] may be classified into [large number > 6] subtypes based on:

• [Classification method 1]
• [Classification method 2]
• [Classification method 3]

[Disease name] may be classified into several subtypes based on:

• [Classification method 1]
• [Classification method 2]
• [Classification method 3]

OR

Based on the duration of symptoms, [disease name] may be classified as either acute or chronic.

OR

If the staging system involves specific and characteristic findings and features:

According to the [staging system + reference], there are [number] stages of [malignancy name] based on the [finding1], [finding2], and [finding3]. Each stage is assigned a [letter/number1] and a [letter/number2] that designate the [feature1] and [feature2].

OR

The staging of [malignancy name] is based on the [staging system].

OR

There is no established system for the staging of [malignancy name].

So far there appear to be three forms of AT:

1. Pure AT where patients present with all/most of the diagnostic symptoms.
2. Attenuated AT where sufferers do not possess all of the diagnostic symptoms.
3. Carrier AT where individuals with a single ATM mutation show an increased risk of cancer (known since the 1970’s).

These are sometimes classified into ‘types’ from I to IV.

• Type I is the classic syndrome with all manifestations.
• Type II lacks some of the typical findings but shows radiosensitivity.
• Type III has the classic clinical findings but is not radiosensitive.
• Type IV shows only some clinical features and is not radiosensitive.