Ataxia, ocular telangiectasia, chromosome instability, and Langerhans cellhistiocytosis in a patient with an unknown breakage syndrome

An 8 year old boy who had Langerhans cell histiocytosis when he was 15 mont hs old showed psychomotor regression from the age of 2 years. Microcephaly, severe growth deficiency, and ocular telangiectasia were also evident. Mag netic nuclear resonance imaging showed cerebellar atrophy. Alphafetoprotein was increased. Chromosome instability after x irradiation and rearrangemen ts involving chromosome 7 were found. Molecular study failed to show mutati ons involving the ataxia-telangiectasia gene. This patient has a clinical p icture which is difficult to relate to a known breakage syndrome, Also, the relationship between the clinical phenotype and histiocytosis is unclear.