Abstract |
Supernumerary marker chromosomes (SMC) were identified in amniocytes from two unrelated fetuses. Fluorescence in situ hybridization (FISH) characterization of the SMC showed they were derived from chromosome 15; SMC(15). Parental karyotyping demonstrated the SMC(15) to be de novo in one fetus and paternally derived in the other. Previous reports showed that the presence or absence of the Prader-Willi/ Angelman syndrome (PWS/AS) critical region, loci D15S11 and distal, in a SMC(15) was associated with an abnormal or normal phenotype, respectively. FISH analysis demonstrated both SMC(15) lacked the D15S11 locus. Because SMC(15) were found at an increased incidence in patients with PWS/AS, we performed methylation analysis at the SNRPN locus to exclude a deletion or uniparental disomy (UPD) of chromosome 15. Both probands showed biparental inheritance at this locus. Based on the FISH and molecular analyses, both fetuses were predicted to have a normal phenotype. The pregnancies were continued and both probands are phenotypically and developmentally normal. These cases illustrate the importance of a combination of family studies, FISH characterization and molecular analyses in SMC(15) identified prenatally. In particular, any chromosome 15 rearrangement identified at prenatal diagnosis should be considered a candidate for UPD15 studies.
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Authors | P D Cotter, C T Ledesma, L G Dietz, S Pusso, M M Wohlferd, J D Goldberg |
Journal | Prenatal diagnosis
(Prenat Diagn)
Vol. 19
Issue 8
Pg. 721-6
(Aug 1999)
ISSN: 0197-3851 [Print] England |
PMID | 10451515
(Publication Type: Case Reports, Journal Article, Review)
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Copyright | Copyright 1999 John Wiley & Sons, Ltd. |
Topics |
- Adult
- Amniocentesis
- Chromosome Aberrations
(diagnosis, genetics)
- Chromosome Disorders
- Chromosomes, Human, Pair 15
- Female
- Humans
- In Situ Hybridization, Fluorescence
- Maternal Age
- Pregnancy
- Pregnancy, High-Risk
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