Holoprosencephaly !

 whenever I studied chromosomal aberrations and associated syndromes , I always got confused between Patau and Eduard's syndromes and that wasn't solved even during my Residency, since those heartbreaking syndromes- luckily- are extremely rare, because I felt that they are a combination of developmental anomalies that carries no link in between , so I couldn't link up all the symptoms together and usually mistaken to replace a symptom for another in describing one of them , luckily Down syndrome is much simpler and more famous as it's more presentable and the common associations would be found in many areas in medicine , but those syndromes and Patau  (trisomy 13) in particular, are rare to find difficult to remeber, Holoprosencephaly allowed me to understand Patau and never be confused with other syndromes.

Holoprosencephaly is a characteristic feature in Patau syndrome, though it may be associated with other genetic and non-genetic conditions, it carries broad spectrum of variation , in fact a Patau face is very unique when you see , Holoprosencephaly means that the prosencephalon failed to divide into the charateristic 2 cerebral hemispheres , so it ends up with one , it has a broad spectrum of presentations and variations , but this made sense to know and connect it with the associated forearm and eye (Micropthalmia) abnormalities and Mental Retardation, also there would be cleft lip and palate.

                                                   MRI demonstrating Holoprosencephaly

                http://www.gfmer.ch/genetic_diseases_v2/gendis_detail_list.php?cat3=1248