Retrospective diagnosis of trisomy 15 in formalin-fixed, paraffin-embedded placental tissue in a newborn girl with Prader-Willi syndrome.
Paternal deletion of 15q11-q13 and maternal uniparental disomy (UPD) of chromosome 15 are the main causes of Prader-Willi syndrome (PWS). The finding of an UPD(15) is associated with increased maternal age. We present a retrospective diagnosis of a trisomy 15 mosaicism confined to the placenta (CPM) after birth of a girl with clinical features of PWS born to a 43-year-old mother. Chromosome analysis after amniocentesis, performed because of advanced maternal age, had shown a normal female karyotype. In peripheral blood cells molecular studies showed the absence of the paternal allele at the SNRPN locus and fluorescence in situ hybridization (FISH) analysis excluded a deletion of the SNRPN locus on both chromosomes 15. Trisomic cells were detected by FISH on nuclei isolated from formalin-fixed, paraffin-embedded placental tissue using a DNA-probe specific for the centromeric region of chromosome 15.
Walczak
C
C
Institute of Anthropology and Human Genetics, Division of Medical Genetics, University of Tübingen, Wilhelmstr. 27, 72074 Tübingen, Germany.
Enders
H
H
Grissinger
K
K
Dufke
A
A
D000328:Adult; D000649:Amniocentesis; D002869:Chromosome Aberrations; D002884:Chromosomes, Human, Pair 15; D005260:Female; D005557:Formaldehyde; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007621:Karyotyping; D008423:Maternal Age; D018895:Microsatellite Repeats; D009030:Mosaicism; D016612:Paraffin Embedding; D010920:Placenta / Q000473:pathology*; D011218:Prader-Willi Syndrome / Q000235:genetics* / Q000473:pathology; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D012189:Retrospective Studies; D014314:Trisomy
D005557:Formaldehyde