Interactive Transcript
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This is an MRI of the brain in a 9-year-old child
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with developmental delay.
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And on the axial T2-weighted image,
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we see several things.
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First of all,
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there's a decreased volume of the cerebral white
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matter and corresponding enlargement
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of the lateral ventricles.
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When we go from the lateral ventricles
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out towards the periphery,
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we can see there's what appears
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to be white matter here.
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And then, something that looks like gray matter.
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In between that,
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we see these little bright areas.
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This is known as the cell sparse zone
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and overlying that is cortex.
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This here is an appearance of lissencephaly with
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paucity of sulcation,
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with underlying band heterotopia.
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Now, in contrast to the first case we saw of
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lissencephaly with band type heterotopia
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in this individual here,
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we don't have band heterotopia
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in the frontal lobes,
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and we have a more normal sulcation
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pattern in the frontal lobes.
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So this is a posterior predominant involvement
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of the lissencephaly with band type heterotopia.
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And it's noted that a posterior predominant
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involvement of this disease process oftentimes
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is related to an abnormality
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in the LIS1 gene.
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So, that is the type of thing that can actually
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be put in a report to possibly
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help guide genetic testing.
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And the genetic testing has implications both
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for the patient, as well as for the family
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and for siblings.
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If I look on the sagittal image,
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we can see the parieto occipital sulcus,
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calcarine fissure, the cunius,
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very, very rudimentary sulcation.
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We're not seeing a lot of surface features,
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the lingual gyrus, very few surface features,
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the precuneus of the parietal lobe.
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Similarly, we're seeing a paucity of sulcation.
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We're seeing the overlying gray matter,
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we're seeing the cell sparse zone,
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and we're seeing this band type heterotopia.
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What I'm going to do is I'm going to show
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this on this T1-weighted image,
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and I'm going to zoom here.
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Here we can see there's a very featureless
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surface to the brain.
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Between the surface and this
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line is the gray matter.
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Subjacent to the gray matter
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is a cell sparse zone,
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and beneath that is the band type
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gray matter heterotopia.
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So, we can see there's all the features of
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lissencephaly with band type heterotopia seen here.
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We see the featureless surface,
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we see the cell sparse zone,
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we see the band-type heterotopia
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subjacent to this.
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As mentioned in this individual,
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we do not see this anteriorly.
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This was not seen anteriorly here.
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There's relative sparing.
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That posterior predominant involvement of lissencephaly
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with band-type heterotopia is often associated with
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abnormalities in the LIS1 gene.
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