All issues > Volume 51(4); 2008

Case Report

Korean J Pediatr. 2008;51(4):426-430. Published online April 15, 2008.

Cytogenetic evaluation of a patient with ring chromosome 9 presenting failure to thrive and developmental delay

Yun Mi YM Park¹, Han Nae HN Nho², Sook Za SZ Kim³, Young Min YM Ahn²

¹Department of Laboratory Medicine, Eulji University School of Medicine, Seoul, Korea
²Department of Pediatrics, Eulji University School of Medicine, Seoul, Korea
³Department of Korea Genetics Research Center, Eulji University School of Medicine, Seoul, Korea

Correspondence Young Min YM Ahn ,Email: aym3216@eulji.or.kr

Abstract

We report clinical, cytogenetic, and fluorescence in situ hybridization (FISH) studies of a patient with ring chromosome 9. She presented with failure to thrive, facial dysmorphysm and mild psychomotor development delay in the absence of major malformations. Peripheral blood karyotype of the patient was 46,XX,r(9)(p24q34). G-band analysis suggested no loss of material in the ring chromosomes. FISH analysis using the subtelomere-specific sequences on chromosome 9p and 9q, revealed 46,XX,r(9)(p24q34),ish r(9)(D9S913-,D9S325+). Failure to detect any hybridization of a probe for the subtelomeric sequences in the ring 9p terminal suggested that this ring arose from breakage in the distal short arm. The cytogenetic and FISH data in our case provided further evidence for the existence of a "complete ring" phenotype with incomplete subtelomeric sequences.

Keywords :Ring chromosome 9, Clinical implication, Cytogenetic, FISH studies