Micronuclei formation may also result from chromosome malsegregation during anaphase. Hypomethylation of cytosine in centromeric and pericentromeric areas and higher-order repeats of satellite DNA in centromeric DNA can result in such chromosomal loss events. Classical satellite DNA is normally heavily methylated at cytosine residues but may become almost fully unmethylated due to ICF syndrome (Immunodeficiency, centromere instability, and facial anomalies syndrome) or after treatment by DNA methyl transferase inhibitors. Since assembly of kinetochore proteins at centromeres is affected by the methylation of cytosine and histone proteins, a reduction in heterochromatin integrity as a result of hypomethylation can interfere with microtubule attachment to chromosomes and with the sensing of tension from correct microtubule-kinetochore connections. Other possible causes of chromosome loss that could lead to micronuclei formation are defects in kinetochore and microtubule interactions, defects in mitotic spindle assembly, mitosis check point defects, abnormal centrosome amplification, and telomeric end fusions that result in dicentric chromosomes that detach from the spindle during anaphase. Micronuclei originating from chromosome loss events and acentric chromosome fragments can be distinguished using pancentromeric DNA probes.