In terms of frequency, is estimated at 2 per 100,000, it has identified in different regions of the world. Some clusters of certain types of autosomal dominant cerebellar ataxia reach a prevalence of 5 per 100,000.

In most cases, between the age of 2 and 4 oculomotor signals are present. Between the age of 2 and 8, telangiectasias appears. Usually by the age of 10 the child needs a wheel chair. Individuals with autosomal recessive cerebellum ataxia usually survive till their 20s; in some cases individuals have survived till their 40s or 50s.

The clinical course of BVVL can vary from one patient to another. There have been cases with progressive deterioration, deterioration followed by periods of stabilization, and deterioration with abrupt periods of increasing severity.

The syndrome has previously been considered to have a high mortality rate but the initial response of most patients to the Riboflavin protocol are very encouraging and seem to indicate a significantly improved life expectancy could be achievable. There are three documented cases of BVVL where the patient died within the first five years of the disease. On the contrary, most patients have survived more than 10 years after the onset of their first symptom, and several cases have survived 20–30 years after the onset of their first symptom.

Families with multiple cases of BVVL and, more generally, multiple cases of infantile progressive bulbar palsy can show variability in age of disease onset and survival. Dipti and Childs described such a situation in which a family had five children that had Infantile PBP. In this family, three siblings showed sensorineural deafness and other symptoms of BVVL at an older age. The other two siblings showed symptoms of Fazio-Londe disease and died before the age of two.

There is no known prevention of spinocerebellar ataxia. Those who are believed to be at risk can have genetic sequencing of known SCA loci performed to confirm inheritance of the disorder.

The prevalence of SCA6 varies by culture. In Germany, SCA6 accounts for 10-25% of all autosomal dominant cases of SCA (SCA itself having a prevalence of 1 in 100,000). This prevalence in lower in Japan, however, where SCA6 accounts for only ~6% of spinocerebellar ataxias. In Australia, SCA6 accounts for 30% of spinocerebellar ataxia cases while 11% in the Dutch.

The disorder has been associated with various mutations in the SLC52A2 and "SLC52A3" genes. This gene is thought to be involved in transport of riboflavin.

BVVL is allelic and phenotypically similar to Fazio–Londe disease and likewise is inherited in an autosomal recessive manner.

The prognosis is generally poor. With early onset, death usually occurs within 10 years from the onset of symptoms. Individuals with the infantile form usually die before the age of 7. Usually, the later the disease occurs, the slower its course is.

Acute cerebellar ataxia is the most common cause of unsteady gait in children. The condition is rare in children older than ten years of age. Most commonly acute cerebellar ataxia affects children between age 2 and 7 years.

There is no known prevention of spinocerebellar ataxia. Those who are believed to be at risk can have genetic sequencing of known SCA loci performed to confirm inheritance of the disorder.

Patients with severe forms of MJD have a life expectancy of approximately 35 years. Those with mild forms have a normal life expectancy. The cause of death of those who die early is often aspiration pneumonia.

Its occurrence is very rare. The infantile form from birth to 2 years of age. The average duration of the infantile form of the illness is usually about 3 years. Onset of the juvenile form presents between two and twelve years of age. Duration of this form is in most cases about 6 years. The adult form from twelve years and older. In younger patients, seizures, megalencephaly, developmental delay, and spasticity are usually present. Neonatal onset is also reported. Onset in adults is least frequent. In older patients, bulbar or pseudobulbar symptoms and spasticity predominate. Symptoms of the adult form may also resemble multiple sclerosis.

There are no more than 500 reported cases.

40 cases were diagnosed in northern Italy between 1940 and 1990. The gene frequency for this autosomal recessive condition was estimated at 1 in 218. In 1989, 16 cases on EOCA were diagnosed in children with a mean onset age of 7.1 In 1990, 20 patients affected by EOCA were studied. It was found that the ataxia of this study's participants affected the pyramidal tracts and peripheral nerves.

Behr syndrome is characterized by the association of early-onset optic atrophy with spinocerebellar degeneration resulting in ataxia, pyramidal signs, peripheral neuropathy and developmental delay.

Although it is an autosomal recessive disorder, heterozygotes may still manifest much attenuated symptoms. Autosomal dominant inheritance also being reported in a family. Recently a variant of OPA1 mutation with phenotypic presentation like Behr syndrome is also described. Some reported cases have been found to carry mutations in the OPA1, OPA3 or C12ORF65 genes which are known causes of pure optic atrophy or optic atrophy complicated by movement disorder.

There is no cure or treatment for GSS. It can, however, be identified through genetic testing. GSS is the slowest to progress among human prion diseases. Duration of illness can range from 3 months to 13 years, with an average duration of 5 or 6 years.

In terms of the genetics of autosomal dominant cerebellar ataxia 11 of 18 known genes are caused by repeated expansions in corresponding proteins, sharing the same mutational mechanism. SCAs can be caused by conventional mutations or large rearrangements in genes that make glutamate and calcium signaling, channel function, tau regulation and mitochondrial activity or RNA alteration.

The mechanism of Type I is not completely known, however Whaley, et al. suggest the polyglutamine product is toxic to the cell at a protein level, this effect may be done by transcriptional dysregulation and disruption of calcium homeostasis which causes apoptosis to occur earlier.

Friedreich's ataxia is the most prevalent inherited ataxia, affecting about 1 in 50,000 people in the United States. Males and females are affected equally. The estimated carrier prevalence is 1:110.

A 1984 Canadian study was able to trace 40 cases of classical Friedreich's disease from 14 French-Canadian kindreds previously thought to be unrelated to one common ancestral couple arriving in New France in 1634: Jean Guyon and Mathurine Robin.

GSS is one of a small number of diseases that are caused by prions, a class of pathogenic proteins highly resistant to proteases.

A change in codon 102 from proline to leucine has been found in the prion protein gene ("PRNP", on chromosome 20) of most affected individuals. Therefore, it appears this genetic change is usually required for the development of the disease.

The progression of symptoms varies widely between each case of FXTAS; the onset of symptoms may be gradual, with progression of the disease spanning multiple years or decades. Alternatively, symptoms may progress rapidly.

FXTAS has shown strong age-dependent penetrance, afflicting older permutation carriers with greater prevalence. Male carriers, age 50 and above have a 30% chance of acquiring FXTAS, while male carriers, age 75 and above, have a 75% chance of developing FXTAS. While initially described to affect male carriers, female carriers of the FMR1 gene mutation have also been found to develop FXTAS. However, due to X-inactivation, female carriers are much less likely to develop classic ataxia and tremor signs for FXTAS, instead demonstrating symptoms such as fibromyalgia, thyroid disease, hypertension, and seizures.

Incidence can vary greatly from type-to-type, and from country-to-country.

In Germany, one study reported an incidence of 1.28 per 100,000.

A study in Italy reported an incidence of 0.56 per 100,000.

A study in Norway reported an incidence of 3.9 per 100,000 using the years from 1978 to 1999, with a lower rate in earlier decades.

Ataxia with telangiectasia is a rare form ataxia that causes chromosomal instability, sensitivity to ionizing radiation, disrupted stress-activated signal transduction pathways and radioresistant DNA synthesis.

The genes that underlie majority of the symptoms for the different types of ataxia are still unknown. A productive cure is still unavailable to prevent the brain degeneration associated with ataxia.

Oculomotor ataxia accompanies gait ataxia which causes dysarthria, muscle weakness, loss of joint position sense and limb dysmetria. In some cases, patients have shown mental retardation and loss of myelinated axons.

Harding ataxia, also known as Early onset cerebellar ataxia with retained reflexes (EOCARR), is an autosomal recessive cerebellar ataxia originally described by Harding in 1981. This form of cerebellar ataxia is similar to Friedreich ataxia including that it results in poor reflexes and balance, but differs in several ways, including the absence of diabetes mellitus, optic atrophy, cardiomyopathy, skeletal abnormalities, and the fact that tendon reflexes in the arms and knees remain intact. This form of ataxia is characterized by onset in the first 20 years, and is less severe than Friedreich ataxia. Additional cases were diagnosed in 1989, 1990, 1991, and 1998.

Onset : Early childhood

Progression: Chronic progressive

Clinical: Cerebellar ataxia plus syndrome / Optic Atrophy Plus Syndrome

Ocular: Optic atrophy, nystagmus, scotoma, and bilateral retrobulbar neuritis.

Other: Mental retardation, myoclonic epilepsy, spasticity, and posterior column sensory loss. Tremor in some cases.

Musculoskeletal

Contractures, lower limbs, Achilles tendon contractures, Hamstring contractures, Adductor longus contractures

Systemic

Hypogonadotrophic hypogonadism.

Treatment of Ramsay Hunt Syndrome Type 1 is specific to individual symptoms. Myoclonus and seizures may be treated with drugs like valproate.

Some have described this condition as difficult to characterize.

Spinocerebellar ataxia type 13 (SCA13) is a rare autosomal dominant disorder, which, like other types of SCA, is characterized by dysarthria, nystagmus, and ataxia of gait, stance and the limbs due to cerebellar dysfunction. Patients with SCA13 also tend to present with epilepsy, an inability to run, and increased reflexes. This cerebellar dysfunction is permanent and progressive. SCA13 is caused by mutations in KCNC3, a gene encoding a voltage-gated potassium channel K3.3. There are two known mutations in this gene causative for SCA13. Unlike many other types of SCA, these are not polyglutamine expansions but, rather, point mutations resulting in channels with no current or altered kinetics.

HDL1 is an unusual, autosomal dominant familial prion disease. Only described in one family, it is caused by an eight-octapeptide repeat insertion in the "PRNP" gene. More broadly, inherited prion diseases in general can mimic HD.