[Genetic diagnosis and analysis for two cases of ring chromosome 22]

To confirm the genetic diagnosis of two patients with ring chromosome 22 syndrome and investigate the mechanism underlying the formation of r(22) and potential genetic causes for the clinical phenotypes.

Cytogenetic and molecular analyses using standard G-banding, fluorescence in situ hybridization and single nucleotide polymorphism array (SNP array) were performed.

For case 1, the karyotype was 46,XY,r(22)(p11q13). SNP array has identified a 7.0 Mb heterozygous deletion at 22q13.2q13.33. For case 2, the karyotype was 46,XY,r(22)(p11q13)[84]/45,XY,-22[6]; SNP array has detected a heterozygous microdeletion of 1.6 Mb at 22q13.33.

With combined application of genetic testing, 2 cases of r(22) syndrome were diagnosed, which has improved the understanding of the genotype-phenotype correlation of r(22).