Clinical, cytogenetic and immunological aspects in 4 cases resembling ataxia telangiectasia.

Four cases resembling ataxia telangiectasia, all characterized by the absence of telangiectasias, are presented. Two are sisters while the other 2 are sporadic cases. The 2 sisters, aged 14 and 12 years, present a progressive neurological disease similar to that characterizing the Louis-Bar syndrome. The clinical picture in 1 of the sporadic cases, a girl aged 13 years, differs from the typical ataxia telangiectasia in having bilateral pyramidal signs in the lower limbs. The last case, a girl aged 8 years, presents an atypical clinical pattern characterized by a severe mental retardation, quite modest cerebellar signs and absence of involuntary movements. The results of the immunological and cytogenetic investigations are presented and discussed.