Chen Chih-Ping, Chern Schu-Rern, Chang Tung-Yao, Tzen Chin-Yuan, Lee Chen-Chi, Chen Wen-Lin, Lee Meng-Shan, Wang Wayseen
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China.
Prenat Diagn. 2003 May;23(5):375-9. doi: 10.1002/pd.602.
To present the prenatal diagnosis and perinatal findings of a de novo terminal deletion of chromosome 7q.
Amniocentesis was performed at 21-weeks gestation owing to a positive result of maternal serum multiple-marker screening. The 30-year-old woman, gravida 2, para 1, had a maternal serum multiple-marker screening test at 18-weeks gestation. The risk of Down syndrome was 1/11 calculated from the gestational age, maternal age, a maternal serum alpha-fetoprotein level of 1.026 multiples of the median (MOM), and a maternal serum free beta-human chorionic gonadotrophin (hCG) level of 8.678 MoM. Cytogenetic analysis of the cultured amniotic fluid cells revealed a de novo terminal deletion of 7q, 46,XX,del(7)(q35). Ultrasonography showed intrauterine growth restriction, microcephaly, and tetralogy of Fallot. The pregnancy was terminated subsequently. Grossly, the placenta was normal. On autopsy, the proband additionally manifested a prominent forehead, hypertelorism, epicanthus, upslanting palpebral fissures, a flat and broad nasal bridge, micrognathia, large low-set ears, overriding toes, and a normal brain. Radiography demonstrated a normal spine. Fluorescence in situ hybridization analysis demonstrated a 7q terminal deletion. Genetic marker analysis showed a maternally derived terminal deletion of chromosome 7(q35-qter).
Fetuses with a de novo 7q terminal deletion may be associated with a markedly elevated maternal serum hCG level and abnormal sonographic findings of intrauterine growth restriction, microcephaly, and congenital heart defects in the second trimester.
介绍一例7号染色体长臂末端新发缺失的产前诊断及围产期发现。
因孕妇血清多项标志物筛查结果阳性，于孕21周行羊膜腔穿刺术。该30岁女性，孕2产1，在孕18周时进行了孕妇血清多项标志物筛查试验。根据孕周、孕妇年龄、孕妇血清甲胎蛋白水平为中位数的1.026倍（MOM）以及孕妇血清游离β-人绒毛膜促性腺激素（hCG）水平为8.678 MoM计算，唐氏综合征风险为1/11。对培养的羊水细胞进行细胞遗传学分析，发现7号染色体长臂末端新发缺失，核型为46,XX,del(7)(q35)。超声检查显示宫内生长受限、小头畸形和法洛四联症。随后终止妊娠。大体检查，胎盘正常。尸检时，先证者还表现为前额突出、眼距增宽、内眦赘皮、睑裂上斜、鼻梁扁平宽阔、小颌畸形、低位大耳、脚趾重叠，大脑正常。X线检查显示脊柱正常。荧光原位杂交分析证实7号染色体长臂末端缺失。基因标记分析显示为母源的7号染色体(q35-qter)末端缺失。
7号染色体长臂末端新发缺失的胎儿可能与孕中期孕妇血清hCG水平显著升高以及宫内生长受限、小头畸形和先天性心脏缺陷等异常超声检查结果有关。
