Replication banding and molecular studies of a mosaic, unbalanced dic(X;15)(Xpter {yields} Xq26.1::15p11 {yields} 15qter)
- Baylor College of Medicine, Houston, TX (United States); and others
We present a patient with a chromosomal mosaicism involving the X chromosome. One cell line is 45,X and the other has a de novo paternally derived dicentric X;15 translocation. Her karyotype is therefore 45,X/45,X,dic(X;15)(Xpter {yields} Xq26.1::15p11 {yields} 15qter) based on G-banding. The presence of 2 centromeres on the derivative X was confirmed by fluorescence in situ hybridization (FISH) and a deletion of Xq26.1 {yields} qter was confirmed by polymerase chain reaction (PCR) using DXS52 and DXYS154. Replication banding studies indicate that the derivative X is late replicating. Based on these studies, it is unclear whether inactivation has spread to proximal 15q. The patient has a unique phenotype distinct from Ullrich-Turner or Prader-Willi syndromes, but includes ataxia and language delay which are commonly seen in Angelman syndrome. These findings are contrary to those anticipated since deficiency of paternal genes at 15q12 typically leads to Prader-Willi syndrome. Molecular analysis of PCR-based polymorphisms of chromosomes 15 and X indicates that uniparental disomy is not present for the X chromosome or chromosome 15 in either cell line. It is hypothesized that her phenotype results from the interaction of the 2 abnormal genotypes. Each abnormality may be diluted by the mosaicism and, in the derivative X line, by the possible variation among cells of inactivation spreading to chromosome 15. 18 refs., 6 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 102884
- Journal Information:
- American Journal of Medical Genetics, Vol. 56, Issue 4; Other Information: PBD: 8 May 1995
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BASIC STUDIES
PATIENTS
PHENOTYPE
CONGENITAL MALFORMATIONS
HEREDITARY DISEASES
GENOTYPE
HUMAN X CHROMOSOME
CHROMOSOMAL ABERRATIONS
MOSAICISM
STRUCTURE-ACTIVITY RELATIONSHIPS
HUMAN CHROMOSOME 15
GENETICS
DNA HYBRIDIZATION
FLUORESCENCE
PROBES
KARYOTYPE
BANDING TECHNIQUES
CENTROMERES
POLYMERASE CHAIN REACTION