PREAXIAL RAY REDUCTION DEFECTS AS PART OF VALPROIC ACID EMBRYOFETOPATHY

It is well known that prenatal exposure of valproic acid (VPA) may be associated with the occurrence of neural tube defects (Robert and Giba ud, 1982). Additional adverse effects related to VPA exposure include craniofacial abnormalities, skeletal defects, brain defects, cardiovas cular defects, and urogenital defects (DiLiberti et al., 1984; Winter et al., 1987; Huot et al., 1987; Jager-Roman et al., 1986; Martinez-Fr ias, 1990). Recently, radial ray reduction has been reported as a seve re type of skeletal defect associated with VPA exposure (Jager-Roman e t al., 1986; Huot et al., 1987; Verloes et al., 1990). We report two a dditional cases of this severe limb reduction defect as part of a broa der pattern of altered morphogenesis in fetuses exposed to VPA and to confirm an association between such severe specific skeletal defects a nd VPA exposure. We briefly review teratologic studies in experimental animals which document the biologic plausibility of this association, and suggest that fetuses exposed to VPA undergo detailed prenatal ult rasonographic evaluation of the limbs.