Prenatal diagnosis of holoprosencephaly (HPE) in a fetus with a recombinant (18)dup(18q)inv(18)(p11.31q11.2)mat

Alobar holoprosencephaly (HPE) was identified by ultrasonography at 18 week s' gestation in a fetus of a 29-year-old G2P0A1 woman. HPE has been describ ed in association with various chromosomal anomalies. Amniocentesis was per formed and a rearrangement of chromosome 18 resembling an isochromosome for the long arm of chromosome 18 was found. Subsequently, the mother was foun d to have a pericentric inversion of chromosome 18 with breakpoints at p11. 31 and q11.2. The karyotype of the fetus was reinterpreted as 46,XX,rcc(18) dup(18q)inv(18)(p11.31q11.2)mat. This is the first case of a parental inver sion leading to a deficiency of 18p11.31 to 18pter associated with HPE. Cop yright (C) 2000 John Wiley & Sons, Ltd.