Molecular characterization of a de novo ring chromosome 6 in a growth retarded but otherwise healthy woman

• Published in: American journal of medical genetics. Part A Vol. 146A; no. 7; pp. 925 - 929
• Main Authors: Höckner, Martina, Utermann, Barbara, Erdel, Martin, Fauth, Christine, Utermann, Gerd, Kotzot, Dieter
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-04-2008; Wiley-Liss
• Subjects: Adult; Base Sequence; Biological and medical sciences; breakpoint; Chromosome aberrations; Chromosomes, Human, Pair 6; DNA Primers; Genomic Imprinting; Growth Disorders - genetics; Humans; Male; Medical genetics; Medical sciences; parental origin; ring chromosome 6; Ring Chromosomes; Chromosomal aberration; Human; Breakpoint; Growth; ring chromosome 6; Chromosome 6; Chromosome C6; De novo; Characterization; Chromosome break; Ring chromosome; Abnormal chromosome; Parental origin; Woman
• ISSN: 1552-4825; 1552-4833
• DOI: 10.1002/ajmg.a.32251

The phenotype of patients with a ring chromosome 6 can be highly variable ranging from almost normal to severe malformations and mental retardation. Size and structure of the ring chromosome as well as the level of mosaicism are important factors for the clinical phenotype. Here, we report on a 25‐year‐old woman with short stature, minor scoliosis, normal fertility, appropriate psychomotor development, minor dysmorphisms, and a de novo ring chromosome 6. Conventional karyotyping as well as molecular cytogenetic and molecular investigations of DUSP22 on 6p and RP1‐191N21.4 on 6q by a new technical approach indicated breakpoints less than 240 kb and less than 190 kb proximal to the telomeres of 6p and 6q, respectively. In addition, formation of the ring chromosome from the paternal chromosome was demonstrated. Thus this case clearly shows that in patients with ring chromosomes without loss of euchromatic material mitotic instability of the ring chromosome is the most important reason for growth retardation and minor congenital anomalies. © 2008 Wiley‐Liss, Inc.