Ring Chromosome 20 Syndrome, or (R)20, is an ultra-rare form of epilepsy with a devastating impact – yet despite huge leaps forward in gene sequencing in recent years, diagnoses are going down ...

In a recent series of 271 fetuses with apparently unbalanced karyotypes, 30.3% (including 43.2% of cases with marker or ring chromosomes) had normal array results, suggesting either variation ...

During this period she described, for the first time, chromosome anomalies such as ring chromosomes, deletions, inversions, and translocations. Cold Spring Harbor. In 1942, McClintock finally ...