Ring chromosome 18: a case report.

Ring chromosomes are rare chromosomal disorders that usually appear to occur de novo. A ring chromosome forms when due to deletion both ends of chromosome fuse with each other. Depending on the amount of chromosomal deletion, the clinical manifestations may be different. So, ring 18 syndrome is characterized by severe mental growth retardation as well as microcephaly, brain and ocular malformations, hypotonia and other skeletal abnormalities. Here we report a 2.5 years old patient with a cleft lip, club foot, mental retardation and cryptorchidism. Chromosomal analysis on the basis of G-banding technique was performed following patient referral to the cytogenetic laboratory. Chromosomal investigation appeared as 46, XY, r(18) (p11.32 q21.32). According to the clinical features of such patients, chromosome investigation is strongly recommended.