Abstract |
Cases of tetrasomy 12p and trisomy 12p are known to be associated with specific phenotypic abnormalities well described in the literature. Here, we report on the unusual case of a partial tetrasomy 12p found in an affected patient and in a mosaic constellation in the patient's mother, who showed no phenotypic abnormality. The index patient was a 16-year-old boy with clinical features similar to the "trisomy 12p syndrome" including mental retardation, macrocephaly, a short nose with anteverted nostrils, and a broad protruding lower lip. G-banding analysis and fluorescence in situ hybridization (FISH) experiments using locus specific YAC DNA probes revealed a derivative chromosome 12 with a partial triplication of the short arm with an inverted copy, flanked by two direct copies. Chromosome analyses in parental lymphocytes showed a chromosomal mosaicism in the phenotypically normal mother, with 12% cells exhibiting the same partial tetrasomy 12p as detected in her son. The allelic pattern of short tandem repeats (STR) in the mother's blood DNA showed that a chimerism can be excluded with high probability. To our knowledge, this is the first report of intrachromosomal triplication on chromosome 12, as well as partial tetrasomy 12p mosaicism. Moreover, as a consequence of the chromosomal aberration in the son it can be concluded that a gonadal mosaicism is present in the mother.
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Authors | Heike Eckel, Rainer Wimmer, Marianne Volleth, Sibylle Jakubiczka, Petra Muschke, Peter Wieacker |
Journal | American journal of medical genetics. Part A
(Am J Med Genet A)
Vol. 140
Issue 11
Pg. 1219-22
(Jun 01 2006)
ISSN: 1552-4825 [Print] United States |
PMID | 16652358
(Publication Type: Case Reports, Journal Article)
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Copyright | Copyright 2006 Wiley-Liss, Inc. |
Topics |
- Abnormalities, Multiple
(genetics, pathology)
- Adolescent
- Chromosome Aberrations
- Chromosome Banding
- Chromosomes, Human, Pair 12
(genetics)
- Craniofacial Abnormalities
- Family Health
- Female
- Gonads
(metabolism)
- Humans
- In Situ Hybridization, Fluorescence
- Intellectual Disability
(pathology)
- Karyotyping
- Male
- Mosaicism
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