Nagarsheth N P, Mootabar H
The Mount Sinai School of Medicine, The Mount Sinai Medical Center, New York, NY 10029, USA.
Clin Genet. 1997 Apr;51(4):260-3. doi: 10.1111/j.1399-0004.1997.tb02466.x.
We describe the first case of a live-born neonate with mosaic tetrasomy 21q confirmed by fluorescence in situ hybridization (FISH). A 38-year-old Caucasian female presented for amniocentesis for maternal age. Initial chromosome analysis of the amniocytes using GTG-banding showed a mos47,XY, +?i(12p)/46,XY karyotype. Follow-up studies with FISH identified the isochromosome as an i(21q); mos47,XY, +i(21q)/46,XY. The patient was delivered at 38+ weeks gestation and umbilical cord blood samples were obtained. Chromosome analysis of 43 cord blood lymphocytes demonstrated a 46,XY karyotype in all cells. However, peripheral lymphocytes taken 1 day after birth showed 1 out of 120 lymphocytes to have an extra chromosome determined to be an i(21q). While initial clinical exam of the neonate revealed similarities to Down syndrome, long-term follow up of our patient will be required to provide the first definitive description of the mosaic tetrasomy 21 syndrome.
我们描述了首例经荧光原位杂交（FISH）确诊的活产新生儿21号染色体长臂四体镶嵌病例。一名38岁的白人女性因年龄因素接受羊水穿刺检查。使用GTG显带技术对羊水细胞进行的初步染色体分析显示核型为mos47,XY, +?i(12p)/46,XY。随后用FISH进行的研究确定等臂染色体为i(21q)；核型为mos47,XY, +i(21q)/46,XY。该患者在妊娠38 +周时分娩，并采集了脐带血样本。对43个脐带血淋巴细胞进行染色体分析，结果显示所有细胞的核型均为46,XY。然而，出生后1天采集的外周淋巴细胞显示，120个淋巴细胞中有1个具有额外的染色体，经确定为i(21q)。虽然对该新生儿的初步临床检查发现其与唐氏综合征有相似之处，但需要对我们的患者进行长期随访，以首次明确描述21号染色体长臂四体镶嵌综合征。
