Nijmegen breakage syndrome is a rare genetic disease presenting at birth with microcephaly, dysmorphic facial features, becoming more noticeable with age, growth delay, and later-onset complications such as malignancies and infections.

Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- oder overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).