Background Ataxia telangiectasia (AT) is an autosomal recessive disease characterised by progressive cerebellar ataxia, oculocutaneous telangiectasia, immunodeficiency, recurrent sinopulmonary infections, sensitivity to ionising radiation, predisposition to cancer and chromosomic instability.The aim of this study is to describe clinical, immunological and mutational features of patients with AT followed in the south of Tunisia.

Patients and Methods Over a period of 22 years (1986–2007), AT was confirmed in 10 patients (8 families). Investigation included immunological and cytogenetic analysis.

Results Parental consanguinity was reported in all families. The mean age of the diagnosis was 21.6 months. Progressive ataxia and ocular telangiectasia was seen in all patients. Ataxia appears at the average of 3 years. The onset of infections occurred at the average age of 2 years 9 months. Lymphopenia was detected in seven cases. The alphafetoprotein level was high in all cases. IgA deficiency was detected in seven patients, high levels of IgM in three and a lower level of IgG in two cases. Chromosome instability was found in six cases, rearrangements of chromosomes 7 and 14 in two cases, defect of cellular proliferation in two cases. The mutational analysis was possible in only two families. In the first family we found a double heterozygotic mutation of the ATM gene in two infants. In the second family another mutation of the ATM gene was found.

Conclusions In this series, the diagnosis of AT was made only in advanced age. Mutation analysis will be important for future clinical and genotypic correlations.