Friedreich ataxia 2

General Information (adopted from Orphanet):

Synonyms, Signs: FRDA2
Number of Symptoms 17
OrphanetNr:
OMIM Id: 601992
ICD-10:
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal recessive
8641704 [IBIS]
Age of onset: Childhood
Adolescent
8641704 [IBIS]

Disease classification (adopted from Orphanet):

Parent Diseases: Friedreich ataxia
 -Rare cardiac disease
 -Rare eye disease
 -Rare genetic disease
 -Rare neurologic disease

Comment:

The phenotype is consistent with Friedreich ataxia 1 (FRDA1), but linkage analysis excluded the FRDA1 locus (OMIM). In a Spanish family with two affected and three unaffected children, the segregated classical Friedreich ataxia did not show the expected linkage. The unique clinical hallmark in this family was the absence of cardiomyopathy after a long-term follow-up in the two affected children. In both patients serum vitamin E levels were normal. (PMID:8641704) Although the patients studied had typical FRDA, one sibpair had the uncommon symptom of retained tendon reflexes. (PMID:10735274)

Symptom Information: Sort by abundance 

1
 (HPO:0000639) Nystagmus 8641704; 10735274; 11523563 IBIS 555 / 7739
2
 (HPO:0000648) Optic atrophy 10735274 IBIS 238 / 7739
3
 (HPO:0001260) Dysarthria 8641704; 10735274; 11523563 IBIS 329 / 7739
4
 (HPO:0002166) Impaired vibration sensation in the lower limbs 8641704 IBIS 26 / 7739
5
 (HPO:0010831) Impaired proprioception 8641704 IBIS 7 / 7739
6
 (HPO:0001251) Ataxia 8641704; 10735274; 11523563 IBIS 413 / 7739
7
 (HPO:0007230) Decreased distal sensory nerve action potential 8641704 IBIS 2 / 7739
8
 (HPO:0002495) Impaired vibratory sensation 10735274; 11523563 IBIS 26 / 7739
9
 (HPO:0001315) Reduced tendon reflexes 8641704; 11523563 IBIS 160 / 7739
10
 (HPO:0003487) Babinski sign 11523563 IBIS 179 / 7739
11
 (HPO:0000819) Diabetes mellitus 11523563 IBIS 131 / 7739
12
 (HPO:0002650) Scoliosis 8641704; 10735274; 11523563 IBIS 705 / 7739
13
 (HPO:0001761) Pes cavus 8641704; 10735274; 11523563 IBIS 225 / 7739
14
 (HPO:0003116) Abnormal echocardiogram 10735274 IBIS 33 / 7739
15
 (HPO:0001638) Cardiomyopathy 10735274 IBIS 192 / 7739
16
 (HPO:0001272) Cerebellar atrophy 10735274 IBIS 197 / 7739
17
 (HPO:0006855) Cerebellar vermis atrophy 8641704; 10735274 IBIS 8 / 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:

Description: (OMIM) Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder characterized by progressive gait and limb ataxia with associated limb muscle weakness, absent lower limb reflexes, extensor plantar responses, dysarthria, and decreased vibratory sense and proprioception. Onset is usually ...
Clinical Description OMIM Smeyers et al. (1996) reported a nonconsanguineous Spanish family in which 2 adult sibs, a male and a female, had a phenotype consistent with Friedreich ataxia, but linkage excluded the FRDA1 locus on chromosome 9q. The patients had ...