[Genetic diagnostic methods in ataxia-telangiectasia (Louis-Bar syndrome)].

PURPOSE: To introduce important genetic diagnostic methods for diagnosis of ataxia telangiectasia.

MATERIAL AND

METHODS

Methods comprised: standard neuropsychiatric and ophthalmologic clinical investigations, analysis of karyograms obtained from cultured lymphocytes, and electronic measurements of lymphocyte nuclei for establishing phases of the cell cycle in radiated and non-radiated lymphocytes that were recovered from a patient.

RESULTS

Cerebellar atrophy in MRT was associated with typical neuroophthalmological symptoms. Structural chromosomal abnormalities with deletion or translocation was found. The cell cycle study showed a characteristic high sensitivity on radiation; particularly high reduction of active cells after radiation was observed in the G1 and S phases. The defective G1/S and S checkpoints were established. The G2/GF ratio was more than threefold higher compared to that of the control group. A very high alpha-fetoprotein level was also noticed.

CONCLUSIONS

A clinical diagnosis of ataxia-telangiectasia should be confirmed through genetic methods.