Friedreich ataxia

General Information (adopted from Orphanet):

Synonyms, Signs:
Number of Symptoms 5
OrphanetNr: 95
OMIM Id: 229300
ICD-10: G11.1
UMLs: C0016719
MeSH: D005621
MedDRA: 10017374
Snomed: 10394003

Prevalence, inheritance and age of onset:

Prevalence: 2
Age of onset:

Disease classification (adopted from Orphanet):

Parent Diseases: Autosomal recessive degenerative and progressive cerebellar ataxia
 -Rare eye disease
 -Rare genetic disease
 -Rare neurologic disease
Cerebellar ataxia with peripheral neuropathy
 -Rare genetic disease
 -Rare neurologic disease
Neurometabolic disease
 -Rare genetic disease
 -Rare neurologic disease
Spinocerebellar degenerescence and spastic paraparesis with an oculomotor anomaly
 -Rare eye disease
 -Rare genetic disease
Syndrome associated with hypertrophic cardiomyopathy
 -Rare cardiac disease
 -Rare genetic disease


This term does not characterize a disease but a group of diseases. Annotations can be found at a more specific level. Friedreich ataxia comprises the following Phenodis entries: Phenodis:9953 Friedreich ataxia 1, OMIM:229300; Phenodis:10825 Friedreich ataxia 2, OMIM:601992;

Symptom Information: Sort by abundance 

(HPO:0002070) Limb ataxia Very frequent [IBIS] 23859346; 10633128 IBIS 41 / 7739
(HPO:0002075) Dysdiadochokinesis Very frequent [IBIS] 23859346 IBIS 40 / 7739
(HPO:0002066) Gait ataxia Very frequent [IBIS] 23859346; 10633128 IBIS 327 / 7739
(HPO:0002522) Areflexia of lower limbs Very frequent [IBIS] 23859346 IBIS 16 / 7739
(HPO:0001260) Dysarthria Very frequent [IBIS] 23859346; 10633128 IBIS 329 / 7739

Associated genes:


ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference
FXN rs104894105 pathogenic RCV000004186.2
FXN rs104894106 pathogenic RCV000004188.2
FXN rs104894107 pathogenic RCV000004189.2
FXN rs104894108 pathogenic RCV000004190.2
FXN rs140987490 pathogenic RCV000004187.2
FXN rs56214919 likely pathogenic RCV000004191.1

Additional Information:

Diagnosis GeneReviews Before the identification of FXN, clinical diagnostic criteria for Friedreich ataxia (FRDA) were established by Geoffroy et al [1976] and refined by Harding [1981]. Following identification of FXN, studies have shown that up to 25% of individuals with GAA expansion mutations in both FXN alleles exhibit clinical findings that differ from the previously established clinical diagnostic criteria [Filla et al 2000]....
Clinical Description GeneReviews Neurologic manifestations. Individuals with typical Friedreich ataxia (FRDA) develop progressive ataxia in childhood or in the early teens, starting with poor balance when walking, followed by slurred speech and upper-limb ataxia. The mean age of onset of symptoms is ten to 15 years [Delatycki et al 1999b]; onset can be as early as age two years and as late as the sixth decade. Gait ataxia, caused by a combination of spinocerebellar degeneration and loss of joint-position sense (proprioception), is the earliest symptom in the vast majority. The poor balance is accentuated when visual input is eliminated, such as in darkness or when the eyes are closed (Romberg sign). Ankle and knee jerks are generally absent, and plantar responses are up-going....
Differential Diagnosis GeneReviews Peripheral neuropathy...
Management GeneReviews To establish the extent of disease in an individual diagnosed Friedreich ataxia (FRDA), the following evaluations are recommended:...
Molecular genetics GeneReviews Information in the Molecular Genetics and OMIM tables may differ from that elsewhere in the GeneReview: tables may contain more recent information. —ED....