Prenatal diagnosis of pure partial monosomy 18p associated with holoprosencephaly and congenital heart defects.

We applied CMA to detect chromosomal variations during a prenatal diagnosis and detected a 4.5Mb pure microdeletion at 18p11.3 that was not detected by conventional karyotyping. Fluorescent in situ hybridization (FISH) analysis was performed to confirm the deletion. Accurate breakpoints of the deletion in this patient were used to build correlations between monosomy 18p and the concomitant phenotypes, particularly holoprosencephaly (HPE), which is rarely reported in monosomy 18p11.3.