Semilobar holoprosencephaly with 21q22 deletion: an autopsy report.

Holoprosencephaly (HPE) is the most common forebrain developmental anomaly with a prevalence of 1:16 000 live-births. Possible aetiological agents include environmental factors and genetic defects such as trisomies (13, 18) and deletions (18p, 7q, 2p and 21q). This complex malformation is due to incomplete division of the cerebral hemisphere. The phenotypes of HPE include alobar, semilobar, lobar and midline interhemispheric fusion variants. Craniofacial anomalies occur in 80% of cases. Severely affected babies die in the neonatal period. Here we report an autopsied case of semilobar HPE with pituitary and adrenal agenesis with 21q22 deletion. Additional findings are noted that would help expand the spectrum of 21q22 deletion.