SLX4 and Friedreich ataxia: Other promising models include the Btbd12 knockout mouse, the ortholog of Slx4 (Fancp) which mimics many features of FA including peripheral cytopenia, reduced fertility, dysmorphic features, ocular abnormalities, hydrocephalus, chromosomal instability, accumulation of damaged chromosomes, hypersensitivity to DNA crosslinking agents and abnormal lymphopoeisis 40.