Often, individuals with ring chromosome 20 syndrome are initially found to have complex partial seizures of frontal lobe origin, though imaging studies do not show a corresponding structural brain abnormality.
22.
Interestingly, the mar del ( 10 ) and bisatellited chromosomes were present in every cell examined, but the ring chromosome was only present in 4 8 % of the cells.
23.
For example, one may question whether the ring chromosomes present in tumors contain a neocentromere following a Class II deletion, because the neocentromere may or may not be present on the ring.
24.
However, fluorescence in situ hybridization ( FISH ) tests remain valuable for diagnosing cases of mosaicism ( mosaic genetics ) and chromosomal rearrangements ( e . g ., ring chromosome, unbalanced chromosomal translocation ).
25.
Occasionally, there is a variation, where the ring chromosome 20 syndrome is characterized by an extra ring chromosome in addition to the two normal ones and hence gives rise to a partial trisomy or supernumerary ring 20.
26.
Occasionally, there is a variation, where the ring chromosome 20 syndrome is characterized by an extra ring chromosome in addition to the two normal ones and hence gives rise to a partial trisomy or supernumerary ring 20.
27.
Particularly, these ring chromosomes involved in breakage-fusion-bridge cycles have a relatively high percentage of prevalence in lipomatous tumors and a lower but still notable prevalence in lung and acute myelogenous leukemia, according to the Mitelman Database.
