Families of SMA Charitable Trust has recently been advised by Prof. Vivian Chan, a Professor from the Medicine Department of the University of Hong Kong that her research team has come up with the method for preimplantation genetic diagnosis (PGD) of fetuses at risk for Spinal Muscular Atrophy (SMA).  At this stage, they would like to recruit mothers who are interested in having another baby again, but do not wish to undergo prenatal testing and subsequently have to terminate an affected pregnancy.  The aim of PGD is to select embryos that are unaffected, and then transfer these to the mother's womb to establish a pregnancy.

The steps involved are:

1. Potential mother undergo ovarian stimulation to develop as many ova as possible.

2. Ova are harvested by gynaecologist. Mothers also receive hCG to prepare her womb. In vitro fertilisation of each ovum with husband's sperm to produce embyro.

3. Embryos are cultured in an incubator for 48 hrs.

4. 1 to 2 cells are then removed from each embryo for PGD.

5. Even when we only take 1cell from the embryo, since we are amplifying for the 'normal' gene, the presence of that 'normal' gene will mean that we have an 'unaffected' embryo.

6. When we have 2 cells from an embryo, concordant results from both cells will mean we are 100% sure of the diagnosis.

7. Transfer of 1 or 2 unaffected embryos back to the mother to establish pregnancy.

8. We advocate that prenatal testing should be made at 18 to 22 weeks gestation to confirm the result of our PGD, this will ensure that the baby born will be free of disease.

The research team will cover the cost of the initial 6 cases. They will be recruited as part of the research programme and will not be charged. If anyone is interested, please contact Mrs. Mary Yim at 2811 1767. The Trust will direct them to the research team for more personal information and enquiries. The entire procedure will be explained to them clearly before they make a decision.

Families of SMA Charitable Trust

種植前遺傳基因診斷
Preimplantation genetic diagnosis (PGD)

本會近日收到自香港大學醫學院內科部陳教授 (Professor Vivian Chan) 的來信，得知其研究小組現對一些可能患有脊髓肌肉萎縮症的胎兒進行有關 種植前遺傳基因診斷 preimplantation genetic diagnosis (PGD) 的研究。 目前來說，研究小組正招募一些打算再生孩子但又不想經產前檢查後又要決定放棄患有脊髓肌肉萎縮症嬰孩的母親。種植前遺傳基因診斷 Preimplantation genetic diagnosis (PGD) 的目的是為母親選取沒有脊髓肌肉萎縮症的胚胎，然後植入母親子宮內令母親懷孕。

以下為有關研究步驟：

1. 候任母親需接受卵巢激素 (ovarian stimulation) 令卵巢盡可能製造更多的卵子作培植之用。

2. 婦科醫生將從母體取出卵子，用體外受精法 (invitro fertilization) 將卵子及丈夫的精子結合以製胚胎 ，並讓母親注射荷爾蒙 (hCG) 令子宮作懷孕之準備。

3. 胚胎於?室培育 48 小時。

4. 從每個胚胎中抽取 1 至 2 個細胞作種植前遺傳基因診斷 preimplantation genetic diagnosis (PGD) 。

5. 即使只從胚胎抽取一個細胞作測檢，由於診斷的科技是將基因加倍擴增，足以讓研究小組選取正常健康的胚胎。

6. 如果能在同一個胚胎取出兩個細胞，而驗出一致 的結果的話，則我們的診斷將會為百分之百準確。

7. 將 1 至 2 個正常的胚胎植入母親體內成孕。

8. 研究小組建議母親於懷孕期第 18 至 22 周接受產前檢查 (prenatal testing) 以確認其 PGD 的結果 ( 肯定嬰孩並沒患有脊髓肌肉萎縮症 ) 。

研究計劃將會招募六個個案，並使用其研究經費支付有關的費用。如有興趣，則可致電 2811 1767 向嚴太查詢。本會會將有興趣人士轉介到研究小組，讓研究小組可更詳細解釋其計劃及解答有關問題，令他們掌握清楚資料後再作決定。

脊髓肌肉萎縮症慈善基金