European Journal of Biomedical and Pharmaceutical Sciences

DEVELOPMENTAL DELAY WITH DYSMORPHISM IN A CHILD WITH RING CHROMOSOME 6

Avvari Srilekha, M.Sc., Madireddy Sujatha, MBBS, PhD and Akka Jyothy, Ph.D. and
Ananthapur Venkateshwari* Ph.D

ABSTRACT

Ring chromosome 6 is a rare sporadic genetic event that occurs mostly de novo with variable clinical phenotypes. It arises as an unusual circular chromosomes following the breakage and reunion of both the telomeres of the same chromosome. Ring chromosomes are unstable during chromosomal segregation and will be lost during meiosis. The proband was a 7 year old child with a history of facial dysmorphism, developmental delay and growth retardation, referred to institute for cytogenetic evaluation. Clinical examination of the child revealed low set ears, mild micrognathia, long philtrum, prominent chin, thin upper lip, flat occiput, mild webbing of neck, low hair line and clinodactyly. Chromosomal analysis revealed 46, XX, r(6) karyotype and microarray analysis revealed no significant deletions /copy number variations / loss of heterozygosity(LOH). The correlation of ring 6 phenotypes with clinical severity remains highly variable as it has multiple functions. Further, studies on molecular characterization of genes involved in ring formation helps in the establishment of accurate genotype/phenotype correlations.

Keywords: Developmental delay, Dysmorphism, Karyotype, Ring chromosome.