ataxia oculomotor apraxia 1 in two siblings of a family:a novel mutation

ataxia oculomotor apraxia1(aoa1) is the most frequent cause of autosomal-recessive cerebellar ataxia in japan,but it is reported from all of the world. the presentation is nearly identical to that of at without the non-neurological features,and accounts for up to 10% of autosomal-recessive cerebellar ataxias.gait imbalance and dysarthria are typical presenting features,oculomotor apraxia typically occurs a few years after symptom onset;the gene,aptx,maps to chromosome 9p13.3 and is expressed in all body tissues.several mutations have been described.here we report two siblings(a girl and a boy) of consanguinuos parents,with history of gait ataxia,titubation and tremor around 5 years old,and oculomotor apraxia after that.the brother showed symptoms of disease earlier and more severe than his sister. after rulling out the common etiologies of progressive ataxia,we did genetic study for aoa1,that showed a homozygous frameshift mutation as c.418_418 del was found.this mutation did not report before so this was a new mutation in aptx gene.