Frequency and phenotypic spectrum of ataxia with oculomotor apraxia 2: a clinical and genetic study in 18 patients.

I. Le Ber
Brain. 2004-01-14; 127(4): 759-767
DOI: 10.1093/brain/awh080

PubMed
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1. Brain. 2004 Apr;127(Pt 4):759-67. Epub 2004 Jan 21.

Frequency and phenotypic spectrum of ataxia with oculomotor apraxia 2: a clinical
and genetic study in 18 patients.

Le Ber I(1), Bouslam N, Rivaud-Péchoux S, Guimarães J, Benomar A, Chamayou C,
Goizet C, Moreira MC, Klur S, Yahyaoui M, Agid Y, Koenig M, Stevanin G, Brice A,
Dürr A.

Author information:
(1)Fédération de Neurologie, Hôpital Pitié-Salpêtrière AP-HP, Paris, France.

Ataxia with oculomotor apraxia type 2 (AOA2) is a newly described autosomal
recessive cerebellar ataxia (ARCA) defined by genetic location to 9q34 of three
families sharing gait ataxia, oculomotor apraxia and/or elevated
alpha-foetoprotein (AFP) levels. We have evaluated 77 families with progressive
non-Friedreich ARCA and have identified six families with a phenotype suggestive
of AOA2. Linkage was confirmed in all six families, with a maximal lod score of
5.91 at D9S1830. We report the first detailed phenotypic study, including
neuropsychological, oculographic and brain imaging investigations, in the largest
series of AOA2 patients yet recruited. The mean age at onset was 15.1 +/- 3.8
years. Sensory motor neuropathy (92%) and choreic or dystonic movements (44%)
were frequent. Oculomotor apraxia was observed in 56% of patients and
characterized by increased horizontal saccade latencies and hypometria. AFP
levels were elevated in 100% of the families, making it a useful biological
marker. This study shows for the first time that AOA2 can be found in Europe,
North Africa and the West Indies, and its relative frequency represents
approximately 8% of non-Friedreich ARCA, which is more frequent than ataxia
telangiectasia and ataxia with oculomotor apraxia type 1 (AOA1), in our series of
adult patients. In adults, AOA2 may be, therefore, the most frequent cause of
ARCA identified so far, after Friedreich’s ataxia.

DOI: 10.1093/brain/awh080
PMID: 14736755 [Indexed for MEDLINE]

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