Experience Sharing on 2007 ACMG Annual Clinical Genetics Meeting

Primary Care Public Health Nursing Service

Experience Sharing on

2007 ACMG Annual Clinical Genetics Meeting

by

FUNG Shun-mei, May, Nursing Officer, Genetic Counselling Unit, Clinical Genetic Service

         This Annual Clinical Genetics Meeting was organized by the American College of Medical Genetics (ACMG) in March 2007. It was held in Nashville Convention Center and Nashville Renaissance Hotel, Nashville, Tennessee, USA. There were about one thousand participants, consisting mainly of geneticists and genetic counsellors from USA and other countries.

         The programme lasted for four and a half days. There were plenary sessions, concurrent symposia, platform presentations, lunch forum, poster presentations and commercial exhibits. The topics included public health genetics, neonatal screening, inborn errors of metabolism, dysmorphology, neurogenetic disorders, cytogenetics, and skeletal dysplasias. The speakers were renowned scholars and practitioners from USA and other western countries such as UK. The objectives of the meeting are to promote the science and practice of clinical genetics.

         Through this meaningful event, I have the chance to broaden my knowledge in the clinical spectrum of various congenital disorders and their current management; to update on the development of newborn screening in USA and to enhance my understanding on the delivery of genetic services in USA.  I would like to take the opportunity to share the views on the following issues:

1.           Population-Based Fragile X Screening

         Fragile X Syndrome is the most common cause of inherited mental retardation and is the most common single gene mutation associated with Autism. The speakers discussed about the possibility of neonatal screening of Fragile X Syndrome and prenatal screening of Fragile X female carriers in USA.

         Recent studies indicated that prenatal screening for Fragile X Syndrome carrier was cost-effective and generally desired by patients. The representatives from commercial companies advocated that prenatal screening for Fragile X Syndrome carrier was necessary. However, the ACMG recommended prenatal screening for Fragile X Syndrome only if there was specific family history indicator, such as Fragile X Syndrome, mental retardation of undiagnosed cause, developmental delay or Autism.

2.  Invasive Prenatal Diagnostic testing

         The session reviewed the role of invasive prenatal diagnostic testing of Trisomy 21 in the management of pregnant women and the feasibility of offering such testing to all pregnant women regardless of maternal age. The safety of invasive testing, the cost-benefit analysis of offering universal invasive testing and the ethical issues inherent in offering invasive prenatal diagnostic testing in all pregnancies were discussed.

         There were a number of recent papers on the advances in prenatal diagnosis documenting lower loss rates of invasive Amniocentesis and Chorionic Villus Sampling. The advance technique of prenatal invasive diagnosis has highlighted debate about the appropriateness of the 35-year¡Vold threshold for offering invasive testing. One of the debates was that invasive prenatal diagnostic testing should be offered to low risk women who might desire definitive diagnosis. Cost-benefit analysis revealed that the cost of providing Amniocentesis against the cost savings in averted Down syndrome births and the consideration of quality-of-life was worthwhile. The analysis has demonstrated that invasive prenatal diagnostic testing was cost-effective for women of all ages.

         In conclusion, all pregnant women should have the autonomy to decide if invasive prenatal testing was required after detailed explanation of the pros and cons of invasive prenatal diagnostic testing regardless of their age.

3.     Effect of Exposure to Bisphenol-A

         Ms Patricia A Hunt from Washington State University presented her incidental finding of the adverse effect of Bisphenol-A (BPA), a synthetic oestrogen used in the production of plastic products, in mice. According to the study, BPA exposure during pregnancy induces chromosomal change in mice. Other effects of BPA exposure included earlier sexual maturity, altered estrus cycles, reduced sperm count, alternations in Prostate development, etc.

4.  Timing of Genetic Counselling and BRCA Testing for Women

         With the discovery of the Breast Cancer Genes (BRCA1 / BRCA2), prophylactic mastectomy is one of the current recommendations for women carrying BRCA mutation in USA. Ms Susan Klugman from Montefiore Medical Centre presented the study of the benefit of known BRCA testing result prior to surgery so that the patient could decide whether to have a lumpectomy and radiation or a bilateral mastectomy. The result of the study indicated that BRCA testing was recommended prior to primary surgery for breast cancer patients.

5.  Impact of false positive and false negative newborn screening results

         Ms Susan E Waisbren from Harvard Medical School and Boston Children Hospital presented their study on the impact of false positive and false negative screening results on families and physicians. The manner in which the physicians communicated results to families affected not only the emotional impact on the family, but also the degree to which the parents adhered to medical recommendations for the child. The majority of paediatricians felt ill-prepared to communicate newborn screening results to families. This often unnecessarily increased parents¡¦ anxiety. Parents confronted with false positive screening result were reported to have increased mental stress and their children were more likely to experience hospitalization for common childhood conditions. Parents who understood the need for repeated tests would be significantly less stressful.

         The conclusion was that parents valued the newborn screening. They were willing to tolerate the increased anxiety caused by a false positive screening result if it could help to avoid a negative outcome.

         Overall, many speakers in the meeting stressed that patients¡¦ autonomy should be respected. Patients should have the right of informed choices.

         The study by Ms Susan E Waisbren, on ¡¥The impact of false positives and false negatives screening results on families and physicians¡¦, reminded me to be more alert and sensitive when informing parents of their babies¡¦ abnormal screening results. Adequate time should be provided to allow parents to express their feelings and to ask questions so as to help reducing their anxiety.

         To conclude, this training was stimulating and rewarding. Besides being well organized, the whole programme was also very practical and useful to genetic nurses who conduct genetic counselling and manage the Neonatal Screening Programme. Therefore, I highly recommend similar training to my colleagues working in Clinical Genetic Service.

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