Cyclopia.
I have about 3 gigs of information/writings I’ve done on defects of the Sonic hedgehog signaling pathway (not the general Hh pathway, but Shh specifically), including a massive presentation I pretty much did on my own because my group members were defective. Of course, in the end, they got great grades in the class, and I got the most mediocre grade ever, because I let them co-opt all my work.
Shh defects cause holoprosencephaly type 3, which results in cyclopias such as this one. There are other causes of cyclopia, but this one is caused by a failure of the brain to divide into two hemispheres, and the Hox genes fail to align the structures along the head (since they’re not activated when the Shh pathway doesn’t work).
Most fetuses with alobar holoprosencephaly are miscarried around 20-22 weeks.





