Which brain defects accompany cyclopia?

We report a fetus with an association of cyclopia without proboscis, aprosencephaly and agnathia. Analysing literature cases and the case presented here we can suggest that: 1) not only alobar holoprosencephaly but also more severe forebrain anomalies can be a brain equivalent of cyclopia; 2) aprosencephaly can be viewed as the earliest known variant of prosencephalic series; and 3) "agnathia-holoprosencephaly" association is etiologically heterogeneous.