Abstract: The preimplantation genetic diagnosis for single gene defects （SGD-PGD ）has been an
embryo genetic analysis established in many European and North America countries，which can be used in
clinical service for those couples who have the transmittable gene mutations in their families. With SGD PGD,
they could give birth to normal baby or carrier of the recessive inherited disorder. The babies from SGD PGD
cases, who had normal genomics, could stop the transmission of the mutation in those families. So, SGD PGD
has been considered as a potential primary prevention of genetic diseases at the gene level. In China, the
population is great, and thus the sub population with inheritable diseases is also great. So, it is important，for
healthy diathesis, national economy and the people’s livelihood, to develop SGD PGD in China. Since 1998，
the writer has taken the evaluation of the SGD PGD feasibility，design and practice for 35 single gene defects.
This article will make a brief commentary for the usage of linkage analysis with haplotyping in SGD PGD.

Key words: SGD-PGD, Haplotyping, Polymerase chain reaction, Auelic drop-out, Short tandem repeats