什么是遗传咨询?

遗传咨询是一个沟通的过程，有它的目标, 减轻人类的痛苦与这一事件有关, 或者发生的风险, 一个家庭的遗传疾病. 咨询师试图通过帮助咨询师实现这一目标:

• 了解医学事实, 包括诊断, 疾病的可能病程, 以及可用的管理
• 认识到遗传和环境对疾病的影响, 以及特定亲属的复发风险
• 了解应对复发风险的备选方案
• 考虑到它们的风险和价值，选择合适的选项, 并按照决定行事
• Make an optimal adjustment to the disorder in an affected family member and/or to the risk of recurrence of that disorder

常见基因测试

连续的屏幕

这两部分的屏幕提供了很高的检出率, 唐氏综合症的早期答案和低假阳性率, trisomy 18 (a rare but severe chromosome problem) and the open neural tube defect (spina bifida). 筛查的第一部分在11周到13周之间进行, 6 days of pregnancy and involves a fetal sonogram to measure the size of the baby's neck (nuchal translucency). Also at this time blood is taken from the mother to measure two proteins, PAPP-A and HCG. The fetal neck measurement and proteins combined can provide an early screen for Down syndrome and trisomy 18. 如果这些结果正常, a second sample of blood is taken from the mother between 15 and 21 weeks 6 days of pregnancy to measure four additional fetal proteins. The first and second parts of the sequential screen are combined to provide a detection rate for Down syndrome and trisomy 18 at 90%, 打开神经管的检出率为80%. 如果第一个合并结果不正常, diagnostic testing such as chorionic villi sampling (CVS) or amniocentesis can be considered.

母体血清AFP筛查开放神经管缺陷

Maternal serum alpha-fetoprotein testing (MSAFP) is a blood test which is offered as a part of routine obstetrical care. 这种筛查试验检查母亲血液中的甲胎蛋白水平. MSAFP水平升高可能与胎儿异常有关, 如脊柱裂和腹壁缺损. 然而，升高的MSAFP结果并不总是与胎儿异常有关. 如果MSAFP异常高，则提供重复测试. 如果重复MSAFP升高, additional tests such as detailed ultrasound evaluation and genetic amniocentesis may be recommended.

母体血清四重筛查

Maternal serum quadruple screening for Down syndrome checks levels of alpha-fetoprotein and unconjugated estriol (made by the baby), 人绒毛膜促性腺激素和二聚体抑制素- a(由胎盘产生). 这些物质进入母亲的血液. Abnormal levels of these substances may indicate an increased risk for fetal Down syndrome. Babies with Down syndrome have three copies of chromosome 21 in each of their cells instead of two (the usual number). Babies with Down syndrome have developmental disabilities and a variety of birth defects. 如果四倍筛查显示患唐氏综合症的风险增加, detailed ultrasound evaluation and the option of genetic amniocentesis may be recommended.

无创产前检查(NIPT)

无创产前检测(NIPT)是一种筛查试验, 对母体血液样本进行检测, which can be performed on women at or after 10 weeks' gestation to help identify fetuses at risk for Down syndrome (trisomy 21), 18三体和13三体. NIPT can also tell the gender of the baby and can identify sex chromosome abnormalities, 比如特纳综合征和克兰费尔特综合征. 21三体、18三体和13三体的检出率高达99%. Turner综合征和Klinefelter综合征的检出率至少为95%. 测试仅限于上面列出的染色体和条件. This test will not identify other abnormalities of those chromosomes and does not detect abnormalities of other chromosomes not tested.

目前, 按照ACOG的建议, NIPT is only being offered to women at increased risk for the conditions listed above. 这包括分娩时年龄在35岁或以上的妇女, women who have had an abnormal serum screening test (such as abnormal sequential screening or quadruple marker screening), women who have an abnormal prenatal sonogram with findings suggestive of a fetal chromosome abnormality, parental balanced Robertsonian translocation with increased risk of fetal trisomy 13 or trisomy 21, or women who have had a prior pregnancy affected with one of the chromosome abnormalities listed above. NIPT is a highly accurate screening test, but is not intended to replace diagnostic prenatal testing. Patients with a high-risk result should be referred for genetic counseling and be offered a fetal karyotype by chorionic villus sampling (CVS) or amniocentesis. 无创产前检查不筛选胎儿开放神经管缺陷. A second trimester blood test called maternal serum alpha fetoprotein screening (MSAFP screening) is available to screen for open neural tube defects.

绒毛膜绒毛取样(CVS)

CVS从怀孕第1013周开始进行. It is a technique for removing a small piece of the developing placenta from within the uterus. Because the placenta and the fetus are genetically the same the placental tissue provides a reliable source of material for performing genetic testing. Due to the small risk of pregnancy complications associated with chorionic villus sampling, 建议在此之前进行遗传咨询.

羊膜穿刺术

羊膜穿刺术, 通常在怀孕16到20周之间进行, is a procedure which allows a pregnancy to be tested for certain kinds of birth defects. 在羊膜穿刺术中, the physician uses ultrasound imaging to guide a thin needle into the amniotic sac and withdraws a small amount of fluid (approximately two tablespoons). The fluid is sent for testing to detect specific disorders such as chromosomal abnormalities and open neural tube defects. Deciding whether or not to have amniocentesis depends on the patient's special risks and concerns. 由于羊膜穿刺术相关的妊娠并发症风险小, 建议在手术前进行遗传咨询.

囊性纤维化携带者筛查

Cystic fibrosis (CF) is one of the most common recessive genetic disorders in Caucasians of Northern European descent, 影响约1 / 2500新生儿. 囊性纤维化导致身体产生异常粘稠的粘液分泌物, 是什么阻碍了许多器官系统的正常运作, 最显著的是呼吸和消化系统. Approximately 4% of Caucasians of Northern European descent carry one abnormal CF gene. 如果父母都是CF携带者, 他们的每一个后代都有25%的几率罹患囊性纤维化. Genetic testing on a blood sample can detect approximately 97% of CF carriers among Ashkenazi Jews and 90% of CF carriers in the Northern European Caucasian population. 其他种族的携带者检出率略低. 如果测试表明父母双方都是携带者, 产前诊断囊性纤维化可能是可用的.

孕前或产前遗传服务转诊指征

• 高龄产妇(分娩时35岁或以上)
• 异常母体血清标志物筛查结果
• 超声检查发现胎儿异常
• 多胎流产(大于等于2胎)和/或死产
• 双亲或其他家庭成员有染色体重排
• 既往子女或家族有染色体异常史
• 父母或子女中有一方已知或怀疑有先天代谢缺陷
• 父母或子女有已知的遗传性/遗传性疾病
• Either parent or child with history of a structural abnormality (such as neural tube defect, 唇腭裂, 或先天性心脏病)
• 有智力迟钝或发育障碍的家族史
• Member of an at-risk ethnic or racial group for which carrier testing and/or prenatal diagnosis may be available
• 血缘关系

地区围产期中心的遗传咨询师

 

Tanya McGuire, MS

Ms. 自1994年以来，McGuire一直是围产期中心的遗传咨询师. 在获得遗传咨询理学硕士学位之前, she worked in the Cytogenetics Laboratory at 上州医科大学 in Syracuse. 她是国家遗传咨询师协会的成员.

Lindsey Guzewicz, MS

Ms. Guzewicz自2020年6月以来一直是围产期中心的遗传咨询师.  She received her Masters Degree in 遗传咨询 from the University of Colorado Anschutz Medical Campus in May 2020.  她是美国遗传咨询委员会认证的遗传咨询师.  她是国家遗传咨询师协会的成员. 公司.