Postnatal confirmation of prenatally diagnosed trisomy 16 mosaicism in two phenotypically abnormal liveborns.
Two phenotypically abnormal liveborns in whom trisomy 16 mosaicism was diagnosed prenatally by amniocentesis are described. Analysis of a percutaneous umbilical blood sample in one case revealed a normal chromosomal complement. Ultrasound examinations performed at the time of amniocentesis were normal. Serial sonography during the late second and third trimesters demonstrated progressive intrauterine growth retardation (IUGR) in both fetuses and a cardiac defect in one. At birth, both infants had dysmorphic features and multiple congenital anomalies. Trisomy 16 mosaicism was confirmed postnatally in both infants in skin fibroblasts; however, peripheral blood samples contained only chromosomally normal cells. The two mosaic trisomy 16 cases described in this report, together with the five confirmed cases reported previously, demonstrate the need for caution in the counselling of patients when trisomy 16 mosaicism is diagnosed prenatally in amniotic fluid samples. Such cases potentially can result in the birth of dysmorphic infants with significant birth defects, growth retardation, and possible developmental disabilities.
Pletcher
B A
BA
Division of Child Development and Human Genetics, North Shore University Hospital-Cornell University Medical College, Manhasset, NY 11030.
Sanz
M M
MM
Schlessel
J S
JS
Kunaporn
S
S
McKenna
C
C
Bialer
M G
MG
Alonso
M L
ML
Zaslav
A L
AL
Brown
W T
WT
Ray
J H
JH
D000015:Abnormalities, Multiple / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics; D000328:Adult; D000649:Amniocentesis; D002869:Chromosome Aberrations / Q000175:diagnosis* / Q000235:genetics; D025063:Chromosome Disorders; D002885:Chromosomes, Human, Pair 16; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D005315:Fetal Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000235:genetics; D005317:Fetal Growth Retardation / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics; D005347:Fibroblasts / Q000166:cytology / Q000648:ultrastructure; D006330:Heart Defects, Congenital / Q000235:genetics / Q000601:surgery; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D009030:Mosaicism / Q000235:genetics*; D010641:Phenotype; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D018566:Pregnancy, High-Risk; D011296:Prenatal Diagnosis; D014314:Trisomy / Q000235:genetics*; D016216:Ultrasonography, Prenatal