Objective: To explore the genetic basis for a child with developmental delay and congenital syndactyly.
Methods: G-banding chromosomal karyotyping and chromosomal microarray analysis (CMA) were performed on peripheral blood sample from the child.
Results: The child was ascertained as 46, XY, r(18)[52]/45,XY,?18[3]. A 18q21.32-q23 deletion was identified by CMA with a size of 19.85 Mb, which has encompassed 99 genes including CTDP1, TXNL4A, TSHZ1, PIGN, RTTN, TNFRSF11A, KDSR and CYB5A.
Conclusion: Clinical phenotype of the patient with ring chromosome 18 is associated with the size of the euchromatin loss and involved genes. As a useful complement to conventional karyotyping, CMA has provided an powerful tool for delineating complex chromosomal aberrations.