(BE WARNED, any linked images contain birth defects, don't click if you can't handle these things).

I haven't seen this suggested yet, and it's perhaps the most visually interesting manifestation of the holoprosencephaly spectrum for my money. In real life, these conditions- much like cyclopia- are incompatible with life, but in a far more immediate fashion than cyclopia tends to be, for reasons that are probably obvious (mostly due to there being no breathing opening).

Otocephaly is mainly characterized by the peculiar location of the ears- mostly on the bottom of the jaw. Agnathia can co-occur or occur without otocephaly, and refers to the mandible failing to form. They will often have a 'proboscis'- the tissue that would have developed into the nose, but has failed and usually become situated somewhere arouund the forehead in a tube-shaped incomplete form.

This disorder is, I feel, unique, because there's a wide range of options in terms of the feature selection, meaning that there'd be a lot more artistic freedom in choosing a specific sprite and design while remaining conceptually accurate to the condition.

There are a few different presentations of the condition that I can show for examples:

https://upload.wikimedia.org/wikipedia/commons/5/56/Otocephaly_and_cyclopia.png
This is probably too similar to cyclopia, but it's a good illustration of the feature rearrangement that takes place. I feel like the 'alien' effect it has is different enough to the pre-existing mutation, though I do understand if they're too close in execution.

https://upload.wikimedia.org/wikipedia/commons/9/91/Otocephaly.png
This one is a little more visiually distinct, with 'emphasis' on the pinna relocation.

https://sonoworld.com/TheFetus/page.aspx?id=3669
This one is particularly interesting to me, with the 'ribboning' of the incorrectly developed brain tissue and the failed development of the cranial vault.

https://f4.bcbits.com/img/a4031136445_10.jpg
Upside down eyes, upside down nose, ears on the bottom. This one is probably the most distinct from cyclopia in terms of visuals.

https://d3i71xaburhd42.cloudfront.net/39799af0a362127440f9f0bb70fad1300aee0407/2-Figure3-1.png
Aural relocation and nasal/mandible features incompletely separated and forming a trunk-like shape.

https://casereports.bmj.com/content/casereports/2017/bcr-2017-220159/F1.large.jpg?width=800&height=600&carousel=1
A little more similar to classic cyclopia: proboscis and hydrocephalic cranial dimensions.

Any thoughts?
Disorders and malformations like these are a bit of a hobby of mine to research, and I have plenty of other ideas for this type of mutation. Most of them being more 'disturbing' and bloody, so they're not the ones I started with for suggestions.