Another patient with chromosome 18 deletion syndrome and juvenile rheumatoid arthritis.

Previously, 4 children with deletion of the long arm of chromosome 18 and chronic arthritis were reported. We present an 8-year-old girl with arthritis, atrial septal defect, external auditory canal atresia, and developmental delay. She is the fifth child reported with 18q- syndrome and juvenile rheumatoid arthritis. Evidence is mounting that genetic loci on chromosome 18 may play a role in the expression of complex autoimmune diseases. Idiopathic arthritis should be considered as a potential additional feature in 18q- syndrome.