Introduction

Recent advances in molecular diagnostics and imaging technology now provide an unprecedented capacity for prenatal identification of a wide range of serious genetic and chromosomal disorders. Early diagnosis has far exceeded our ability to correct debilitating disorders, especially those for which there is no satisfactory postnatal treatment, and this has been the impetus for research into prenatal therapy. The rationale is that early detection allows early treatment, thus potentially curing a uniformly fatal disorder or preventing irreversible postnatal sequelae, especially those affecting the central nervous system.

Stem cells hold far-reaching possibilities for the treatment of both acquired and congenital diseases. They can be used therapeutically to replace dysfunctional cells and tissues, or via ex vivo genetic manipulation to reconstitute a missing gene product (stem cell-based gene therapy). Stem cell transplantation in utero offers the exciting prospect of effectively treating inherited haematological, metabolic and other early-onset genetic diseases. This chapter addresses the current status of fetal stem cell therapy, its limitations and its future development.

Sources of stem cells

Stem cells are rare primitive cells that share two distinct properties regardless of their source:

1. the capacity for self-renewal

2. multi-lineage potential.

Embryonic stem (ES) cells from the inner cell mass have the advantage of pluripotency or even totipotency but their clinical use is hindered by the real possibility of teratoma formation in vivo, which largely limits clinical application to tissue engineering rather than cell therapy.