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This is an MRI of the brain in a newborn.

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In a child who had an abnormal fetal ultrasound,

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we can see right away that there's an abnormal

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configuration of the ventricular system

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on this T2-weighted image.

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So, there's a monoventricle.

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There's no two separate lateral ventricles.

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There's one big, relatively amorphous ventricle.

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Additionally,

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we don't have any intrahemispheric fissure.

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The cortex,

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which is relatively featureless

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of one cerebral hemisphere,

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goes all the way over to the contralateral side.

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We see likely what is a single anterior

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cerebral artery.

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Additionally, we see fusion of both thalami.

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Now,

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the cerebral hemispheres are part of

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the brain called the telencephalon.

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The thalami are a part of the brain

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called the diencephalon.

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Those are the parts of the brain in a five

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part mature brain, but developmentally,

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in a three-part brain,

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the diencephalon and telencephalon come

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from what's called the prosencephalon.

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So an abnormality in the prosencephalon,

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which we see here with the telencephalic

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component and the diencephalic component,

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is a prosencephalic abnormality.

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This is referred to as holoprosencephaly.

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Holo meaning one prosencephalon.

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So there's one prosencephalon.

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The two sides of the brain did not

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split apart from one another.

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This is a very severe case of holoprosencephaly

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called alobar holoproseencephaly.

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Now, the posterior fossa contents

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can be closer to normal,

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but the cerebral hemispheres are very abnormal.

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There's featureless cortex,

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decreased white matter volume,

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monoventricular abnormality of the

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deep gray nuclei.

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Additionally,

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we notice the globes are too close together.

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The globes, as a rule of thumb,

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you should be able to put about one

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globe in between the two of them.

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This is much less than that.

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So this is signs of hypotelorism,

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which is associated with craniofacial

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abnormalities,

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and holoprosencephaly is often associated with

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craniofacial and other midline abnormalities.

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We can see in this individual here,

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here on this sagittal image,

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here's the pons,

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here's the medulla oblongata.

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Here's the midbrain.

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Going forward,

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we have a very amorphous conglomeration.

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We do not see discrete mammillary bodies.

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We do not see discrete hypothalamus.

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So, all of this is very abnormal.

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This bright area here is likely a neurohypophyseal

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area of T1 shortening,

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but it's not within the sella turcica itself.

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So, it is not uncommon for children with

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holoprosencephaly to have other midline defects.

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Pituitary abnormalities,

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which goes along with endocrine dysfunction,

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craniofacial abnormalities, including clefts,

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as well as

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bony abnormalities of the

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spine and other things.

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So, this is a very severe holoprosencephaly

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spectrum disorder.

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Known as alobar holoprosencephaly.