Clinical and molecular-cytogenetic studies in seven patients with ring chromosome 18.
Am J Med Genet
; 101(3): 226-39, 2001 Jul 01.
Article
en En
| MEDLINE
| ID: mdl-11424138
We report the results of detailed clinical and molecular-cytogenetic studies in seven patients with ring chromosome 18. Classical cytogenetics and fluorescence in situ hybridization (FISH) analysis with the chromosome 18 painting probe identified five non-mosaic and two complex mosaic 46,XX,dup(18)(p11.2)/47,XX,dup(18)(p11.2),+r(18) and 46,XX,dup(18)(p11.32)/47,XX,dup(18)(p11.32),+r(18) cases. FISH analysis was performed for precise characterization of the chromosome 18 breakpoints using chromosome 18-specific short-arm paint, centromeric, subtelomeric, and a panel of fifteen Alu- and DOP-PCR YAC probes. The breakpoints were assessed with an average resolution of approximately 2.2 Mb. In all r(18) chromosomes, the 18q terminal deletions ranging from 18q21.2 to 18q22.3 ( approximately 35 and 9 Mb, respectively) were found, whereas only in four cases could the loss of 18p material be demonstrated. In two cases the dup(18) chromosomes were identified as inv dup(18)(qter-->p11.32::q21.3-->qter) and inv dup(18)(qter-->p11.32::p11.32-->p11.1: :q21.3-->qter)pat, with no evidence of an 18p deletion. A novel inter-intrachromatid mechanism of formation of duplications and ring chromosomes is proposed. Although the effect of "ring instability syndrome" cannot be excluded, the phenotypes of our patients with characteristic features of 18q- and 18p- syndromes are compared and correlated with the analyzed genotypes. It has been observed that a short neck with absence of cardiac anomalies may be related to the deletion of the 18p material from the r(18) chromosome.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cromosomas en Anillo
/
Cromosomas Humanos Par 18
Tipo de estudio:
Prognostic_studies
Límite:
Child
/
Child, preschool
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Am J Med Genet
Año:
2001
Tipo del documento:
Article
País de afiliación:
Polonia
Pais de publicación:
Estados Unidos