[Molecular cytogenetic analysis of a case with ring chromosome 3 syndrome].

To investigate the genetic cause for a child with developmental delay and congenital heart disease through molecular cytogenetic analysis.G-banded karyotyping and chromosomal microarray analysis (CMA) were performed for the patient and his parents.The proband's karyotype was detected as ring chromosome 3, and a 3q26.3-25.3 deletion encompassing 45 genes has been found with CMA. Testing of both parents was normal.Clinical phenotype of the patient with ring chromosome 3 mainly depends on the involved genes. It is necessary to combine CMA and karyotyping for the diagnosis of ring chromosome, as CMA can provide more accurate information for variations of the genome.