• Journal of Genetic Medicine
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• v.6 no.2
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• pp.131-145
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• 2009

Preimplantation genetic diagnosis (PGD) has become an assisted reproductive technique for couples who are at risk that enables them to have unaffected baby without facing the risk of pregnancy termination after invasive prenatal diagnosis. The molecular biology and technology for single-cell genetics has reached an extremely high level of accuracy, and has enabled the possibility of performing multiple diagnoses on one cell using whole genome amplification. These technological advances have contributed to the avoidance of misdiagnosis in PGD for single gene disorders. Polymerase chain reaction (PCR)-based PGD will lead to a significant increase in the number of disorders diagnosed and will find more widespread use, benefiting many more couples who are at risk of transmitting an inherited disease to their baby. In this review, we will focus on the molecular biological techniques that are currently in use in the most advanced centers for PGD for single gene disorders, including biopsy procedure, multiplex PCR and post-PCR diagnostic methods, and multiple displacement amplification (MDA) and the problems in the single cell genetic analysis.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.2
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• pp.99-110
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• 2008

Objectives: Preimplantation genetic diagnosis (PGD) has become an assisted reproductive technique for couples carrying genetic conditions that may affect their offspring. Osteogenesis imperfecta (OI) is an autosomal dominant disorder of connective tissue characterized by bone fragility and low bone mass. At least 95% of cases are caused by dominant mutations in the COL1A1 or COL1A2. In this study, we report on our experience clinical outcomes with 5 PGD cycles for OI in two couples. Methods: Before clinical PGD, we assessed the amplification rate and allele drop-out (ADO) rate of alkaline lysis and nested PCR protocol using heterozygous patient's single lymphocytes in the pre-clinical diagnostic tests for OI. We performed 5 cycles of PGD for OI by nested PCR for the causative mutation loci, COL1A1 c.2452G>A and c.3226G>A, in case 1 and case 2, respectively. The PCR products were analyzed by agarose gel electrophoresis, restriction fragment length polymorphism (RFLP) analysis with HaeIII restriction enzyme in the case 1 and direct DNA sequencing. Results: We confirmed the causative mutation loci, COL1A1 c.2452G>A in case 1 and c.3226G>A in case 2. In the pre-clinical tests, the amplification rate was 94.2% and ADO rate was 22.5% in case 1, while 98.1% and 1.9% in case 2, respectively. In case 1, a total of 34 embryos were analyzed and 31 embryos (91.2%) were successfully diagnosed in 3 PGD cycles. Eight out of 19 embryos diagnosed as unaffected embryos were transferred in all 3 cycles, and in the third cycle, pregnancy was achieved and a healthy baby was delivered without any complications in July, 2005. In case 2, all 19 embryos (100.0%) were successfully diagnosed and 4 out of 11 unaffected embryos were transferred in 2 cycles. Pregnancy was achieved in the second cycle and the healthy baby was delivered in March, 2008. The causative locus was confirmed as a normal by amniocentesis and postnatal diagnosis. Conclusions: To our knowledge, these two cases are the first successful PGD for OI in Korea. Our experience provides a further demonstration that PGD is a reliable and effective clinical techniques and a useful option for many couples with a high risk of transmitting a genetic disease.

• 대한생식의학회:학술대회논문집
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• 2001.11a
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• pp.13-22
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• 2001

• Clinical and Experimental Reproductive Medicine
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• v.32 no.4
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• pp.293-300
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• 2005

연구목적: 단일 유전자 이상에 대한 착상전 유전진단을 성공적으로 시행하기 위해서는 효과적이고 신뢰도가 높은 PCR 방법의 확립이 중요하다. 본 연구에서는 alkaline lysis와 duplex nested PCR 방법을 단일 림프구와 할구의 유전자 분석에 적용하여 그 효용성을 확인하고자 하였다. 재료 및 방법: 단일 유전자의 이상이 확인된 Duchenne muscular dystrophy (DMD), ornithine transcarbamylase (OTC) 결핍증과 epidermolysis bullosa (EB) 가계의 대상자들에서 채취한 단일 림프구와 공여 받은 배아의 할구를 이용하여 각각 PCR, restriction fragment length polymorphism (RFLP)와 direct DNA sequencing 분석을 시행하였다. 이러한 분석에서 유전자 증폭률 (amplification rate)과 두개의 allele 중에서 하나의 allele이 증폭되지 않는 allele drop-out (ADO) 빈도에 대해 살펴보았다. 결 과: 단일 림프구와 할구를 이용한 PCR 방법의 유전자 증폭률은 DMD에서 91.1%와 81.8%, OTC 결핍증에서 96.0%와 78.1%, EB에서 91.3%와 90.0%를 각각 나타냈으며, ADO 빈도는 OTC 결핍증에서 13.3%, EB에서 16.8%로 관찰되었다. 결 론: 본 연구에서 적용한 alkaline lysis와 duplex nested PCR 방법은 단일 유전자에 대한 착상전 유전진단에 성공적으로 적용할 수 있는 방법으로 생각되며, ADO 빈도를 최소화할 수 있는 효율적인 방법의 개발에 대한 지속적인 연구가 필요하다.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.3
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• pp.179-187
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• 2006

Objectives: The risk of aneuploidies of embryos increases in advanced maternal age or parental karyotype abnormality and it results in poor reproductive outcomes such as recurrent spontaneous abortion (RSA) or repeated implantation failure (RIF). Preimplantation genetic diagnosis for aneuploidy screening (PGD-AS) can be applied for better ART outcome by selecting chromosomally normal embryos. The aim of this study is to evaluate the clinical outcome of PGD-AS and which group can get much benefit from PGD-AS among the patients expected to have poor reproductive outcome. Methods: In 42 patients, 77 PGD cycles were performed for aneuploidy screening. Patients were allocated to 3 groups according to the indication of PGD-AS: group I-patients with old age (${\geq}37$) and RIF more than 3 times (n=11, mean age=42.2 yrs.), group II-patients with RSA (${\geq}3$ times) associated with aneuploid pregnancy (n=19, mean age=38.9 yrs.), group III-parental sex chromosome abnormality or mosaicism (n=18, mean age=29.6 yrs.) including Turner syndrome, Klinefelter syndrome and 47, XYY. PGD was performed by using FISH for chromosome 13, 16, 18, 21, X and Y in group I and II, and chromosome X, Y and 18 (or 17) in group III. Results: Blastomere biopsy was successful in 530 embryos and FISH efficiency was 92.3%. The proportions of transferable embryos in each group were $32.5{\pm}17.5%$, $23.0{\pm}21.7%$ and $52.6{\pm}29.2%$ (mean ${\pm}$ SD), respectively, showing higher normal rate in group III (group II vs. III, p<0.05). The numbers of transferred embryos in each group were $3.9{\pm}1.5$, $1.9{\pm}1.1$ and $3.1{\pm}1.4$ (mean ${\pm}$ SD), respectively. The clinical pregnancy rates per transfer was 0%, 30.0% and 20.0%, and it was significantly higher in group II (group I vs. group II, p<0.05). The overall pregnancy rate per transfer was 19.6% (10/51) and the spontaneous abortion rate was 20% (2/10) of which karyotypes were euploid. Nine healthy babies (one twin pregnancy) were born with normal karyotype confirmed on amniocentesis. Conclusion: Our data suggests that PGD-AS provides advantages in patients with RSA associated with aneuploidy or sex chromosome abnormality, decreasing abortion rate and increasing ongoing pregnancy rate. It is not likely to be beneficial in RIF group due to other detrimental factors involved in implantation.

• Clinical and Experimental Reproductive Medicine
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• v.34 no.3
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• pp.179-188
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• 2007

Objectives: Many neurological diseases are known to be caused by expansion of trinucleotide repeats (TNRs). It is hard to diagnose the alteration of TNRs with single cell level for preimplantation genetic diagnosis (PGD). In this study, we describe methods optimized for PGD of TNRs related diseases such as Huntington's disease (HD), spinocerebellar ataxia 3 (SCA3) and fragile X syndrome (FXS). Methods: We performed the preclinical assays with heterozygous patient's lymphocytes by single cell PCR strategy. Fluorescent semi-nested PCR and fragment analysis using automatic genetic analyzer were applied for HD and SCA 3. Whole genome amplification with multiple displacement amplification (MDA) method and fluorescent PCR were carried out for FXS. Amplification and allele drop-out (ADO) rate were evaluated in each case. Results: The fluorescent semi-nested PCR of single lymphocyte showed 100.0% of amplification and 14.0% of ADO rate in HD, and 94.7% of amplification and 5.6% of ADO rate in SCA3, respectively. We could not detect the PCR product of CGG repeats in FXS using the fluorescent semi-nested PCR alone. After applying the MDA method in FXS, 84.2% of amplification and 31.3% of ADO rate were achieved. Conclusions: Fluorescent semi-nested PCR is a reliable method for PGD of HD and SCA3. The advanced MDA method overcomes the problem of amplification failure in CGG repeats of FXS case. Optimization of methods for single cell analysis could improve the sensitivity and reliability of PGD for complicated single gene disorders of TNRs.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.1
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• pp.19-38
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• 2008

• 대한생식의학회:학술대회논문집
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• 2005.11a
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• pp.110-110
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• 2005

• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.71-72
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• 2004

• 대한생식의학회:학술대회논문집
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• 2007.11a
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• pp.106.2-107
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• 2007