[Clinical phenotype and genetic analysis of twelve children with ring chromosomes]

To explore the prevalence and clinical manifestations of ring chromosomes among children featuring abnormal development.

From January 2015 to August 2021, 7574 children referred for abnormal development were selected, and their peripheral blood samples were subjected to G-banded chromosomal karyotyping analysis.

Twelve cases of ring chromosomes were detected, which have yielded a prevalence of 0.16% and included 1 r(6), 2 r(9), 1 r(13), 1 r(14), 2 r(15), 1 r(21) and 3 r(X). The children had various clinical manifestations including growth and mental retardation, limb malformation, and congenital heart disease. For two children with r(9) and two with r(15) with similar breakpoints, one child with r(9) and one with r(15) only had growth retardation, whilst another with r(9) and another with r(15) also had peculiar facies and complex congenital heart disease. The r(X) has featured some manifestations of Turner syndrome.

Ring chromosomes are among the common causes for severe growth and mental retardation in children with diverse clinical phenotypes. Clinicians should pay attention to those with developmental anomalies and use chromosomal analysis to elucidate their genetic etiology.