Stetten Gail, Escallon Cathleen S, South Sarah T, McMichael Joseph L, Saul Daniel O, Blakemore Karin J
Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-2501, USA.
Am J Med Genet A. 2004 Dec 15;131(3):232-9. doi: 10.1002/ajmg.a.30363.
Chromosomal mosaicism was found in 38 of 4,000 chorionic villus samples examined from 1998 to 2003. A small fraction of these (5/38) were confirmed as true mosaics by analysis of amniotic fluid. Twenty-nine cases that fit the definition of confined placental mosaicism were followed with clinical and cytogenetic analysis throughout the pregnancy, at birth and in a few cases into infancy. This was done to determine the prognostic interpretation of prenatal cytogenetic results from multiple specimens in a single pregnancy and thus allow for reevaluation of the genetic counseling. In 2 of these 29 cases, low-level mosaicism was found in the neonate, and in 1 of these the chromosome abnormality is probably the cause of the resulting minor phenotypic abnormalities. Families face unique difficulties when confined placental mosaicism is the prenatal diagnosis, and it is extremely important that the counseling they receive takes into consideration the unlikely possibility of the placental abnormality appearing in fetal tissues.
在1998年至2003年检查的4000份绒毛膜绒毛样本中，发现38例存在染色体嵌合现象。其中一小部分（5/38）经羊水分析确认为真正的嵌合体。对符合局限性胎盘嵌合定义的29例病例在整个孕期、出生时以及少数情况下直至婴儿期进行了临床和细胞遗传学分析。这样做是为了确定单次妊娠中多个样本的产前细胞遗传学结果的预后解释，从而重新评估遗传咨询。在这29例病例中的2例中，新生儿发现了低水平嵌合现象，其中1例的染色体异常可能是导致轻微表型异常的原因。当产前诊断为局限性胎盘嵌合时，家庭面临独特的困难，他们接受的咨询考虑到胎盘异常出现在胎儿组织中的可能性极小，这一点极其重要。
