Ring chromosome 22

The associated signs and symptoms depend largely on where the breakpoint occurs on chromosome 22 and how much genetic material has been lost on the long (q) arm. Genetic material lost on the short (p) arm is usually irrelevant and does not cause physical or intellectual features. The breakpoints on the long (q) arm can be difficult to determine; but in ring chromosome 22, they are most likely to happen somewhere in the terminal segment of the distal band 22q13.^[2]

In general, there is limited information on how chromosome abnormalities like ring chromosome 22 impact growth and development. Since each abnormality is usually so rare, there are few cases to learn from, let alone conduct research. It is generally difficult to say what the future will hold for affected individuals, because even when the chromosome abnormalities are similar, the health problems can vary widely. 

Over 100 cases have been reported on ring chromosome 22. While there is no consistent clinical picture, frequent findings of ring chromosome 22 include developmental delay, moderate to severe learning difficulties or intellectual disabilities, small head, absent or delayed speech, hypotonia, unsteady manner of walking, hyperactivity, autistic behaviors, seizures, and growth delay. Some affected individuals may also have relatively mild, non-specific physical features, whereas others may have more distinctive, potentially severe physical abnormalities.^[1][2][3]