Linkage to chromosome 13q11-12 of an autosomal recessive cerebellar ataxia in a Tunisian family.
OBJECTIVE
To report the clinical findings and the genetic linkage mapping of an autosomal recessive cerebellar ataxia associated to peripheral neuropathy, showing an early onset cerebellar ataxia with retained tendon reflexes (EOCA) phenotype.


BACKGROUND
EOCA is a clinical syndrome delimited by Harding distinguished from Friedreich's ataxia (FA) mainly by the preservation of tendon reflexes. Molecular genetic study of patients with EOCA has demonstrated genetic heterogeneity. A form of autosomal recessive spastic ataxia has been described in Charlevoix Saguenay area in Quebec (ARSACS); the gene responsible has been mapped to chromosome 13q.


METHODS
Genetic linkage analysis was performed on 18 members of a large family including 8 of 9 members with EOCA. After exclusion of FA and ataxia with vitamin E deficiency loci as well as loci of autosomal dominant cerebellar ataxias, we performed a linkage analysis to markers of 13q11-12 region.


RESULTS
The 9 affected members of this family showed stereotyped clinical features with cerebellar ataxia, pyramidal syndrome, and a variable degree of axonal peripheral neuropathy. Linkage was detected between the disease locus and the microsatellite marker D13S232. Surrounding markers to D13S232 confirmed the linkage and showed the homozygosity of the affected members.


CONCLUSIONS
The family reported here showed the same locus as autosomal recessive spastic ataxia Charlevoix Saguenay disease.
Mrissa
N
N
Institut National de Neurologie, Tunis, Tunisia.
Belal
S
S
Hamida
C B
CB
Amouri
R
R
Turki
I
I
Mrissa
R
R
Hamida
M B
MB
Hentati
F
F
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001706:Biopsy; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics*; D005073:Evoked Potentials, Somatosensory / Q000235:genetics; D005260:Female; D005808:Genes, Recessive / Q000235:genetics; D008040:Genetic Linkage / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D008126:Lod Score; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology; D009431:Neural Conduction / Q000235:genetics; D010375:Pedigree; D010543:Peroneal Nerve / Q000473:pathology; D013132:Spinocerebellar Degenerations / Q000453:epidemiology / Q000235:genetics*; D014416:Tunisia / Q000453:epidemiology
D005819:Genetic Markers