Dreux Sophie, Olivier Camille, Dupont Jean-Michel, Leporrier Nathalie, Oury Jean-François, Muller Françoise
Biochimie-Hormonologie, Hôpital Robert Debré, AP-HP, Paris.
Prenat Diagn. 2008 Aug;28(8):699-703. doi: 10.1002/pd.2051.
To determine if the second-trimester maternal serum markers (MSM) screening for Down syndrome (DS) is efficient in DS mosaicism or structural rearrangement cases.
DS mosaic or translocation cases were reviewed from databases of routine MSM DS screening. The control group consisted of 977 trisomy 21 cases included in a series of 854 902 patients (routine screening). DS risk was calculated by combination of maternal age and MSM [alpha-fetoprotein (AFP) and human choriogonadotrophin (hCG) or free beta-hCG and/or uE3] expressed in multiples of median (MoM). Mosaic DS cases were divided into three groups, < 10%, 10-49%, and >or= 50% trisomy 21 cells. Translocation DS cases were divided into three groups, isochromosome, Robertsonian, or reciprocal translocation. Detection rate (DR) and MoMs were evaluated in each group.
As many as 76 cases of nonstandard trisomy 21 were collected. For mosaic DS cases (n = 43) DR was 69.8% (not significantly different from the 70.8% of control group). When mosaicism was less than 10%, the DR dropped to 25%. For translocation DS cases (n = 33) DR was 75.7% (not significantly different from control group) whatever the types of translocation.
In the nonstandard DS cases, second-trimester MSMs gave the same detection rate as for standard trisomy 21, except the cases with low-level mosaicism (<10%).
确定孕中期母血清标志物（MSM）筛查唐氏综合征（DS）在DS嵌合体或结构重排病例中是否有效。
从常规MSM DS筛查数据库中回顾DS嵌合体或易位病例。对照组由854902例患者系列中的977例21三体病例组成（常规筛查）。通过结合孕妇年龄和以中位数倍数（MoM）表示的MSM[甲胎蛋白（AFP）和人绒毛膜促性腺激素（hCG）或游离β-hCG和/或雌三醇（uE3）]计算DS风险。嵌合型DS病例分为三组，21三体细胞<10%、10 - 49%和≥50%。易位型DS病例分为三组，等臂染色体、罗伯逊易位或相互易位。评估每组的检出率（DR）和MoM。
共收集到76例非标准21三体病例。对于嵌合型DS病例（n = 43），DR为69.8%（与对照组的70.8%无显著差异）。当嵌合率小于10%时，DR降至25%。对于易位型DS病例（n = 33），无论易位类型如何，DR为75.7%（与对照组无显著差异）。
在非标准DS病例中，孕中期MSM的检出率与标准21三体相同，但低水平嵌合（<10%）的病例除外。
