Ring Chromosome 3

Ring chromosome 3 (RC3) is an ultra-rare constitutional chromosomal abnormality and has been described in only 13 live-born patients since 1966. Cytogenetic analysis detected the short-arm and long-arm breakpoints in RC3 with different banding resolutions. Chromosome microarray analysis defined genomic imbalances in two patients of RC3. The most frequently seen clinical features for patients of RC3 include growth retardation, intellectual disability, microcephaly, and facial dysmorphism. Genotype–phenotype correlations for genes in the distal deletions of 3p have been suggested. Comprehensive cytogenomic analysis should be performed to define the ring structure, dynamic mosaicism, and genomic imbalance. Proper genetic counseling and clinical management should be recommended to patients and their families.