Ring Chromosome 11

Ring chromosome 11 (RC11) is a rare chromosomal abnormality with a limited number of cases reported in the literature thus far. Patients with RC11 resulting from an 11q deletion often present with Jacobsen syndrome features. Clinical presentations among RC11 patients vary greatly. Common clinical manifestations include growth delays, cognitive impairment, microcephaly, facial dysmorphism, behavioral problems, congenital cardiac defects, and skin discoloration. Other less frequent clinical presentations are thrombocytopenia, endocrine dysfunction, skeletal abnormalities, and eye abnormalities. Wilms tumor has been reported in patients with RC11 with 11p15 aberration. Most RC11 cases are reported in females; familial RC11 is rare. Most RC11s were studied by conventional karyotyping, and few were molecularly characterized by chromosomal microarray. Close genotype–phenotype correlation has yet to be established in RC11.