Figure 1.

Clinical and Imaging Features

(A) Pictures of individuals 1 (a, b), 2 (c, d), 3 (e, f), 5 (g, h), 7 (i, j), and 11 (k, l): variable facial dysmorphism.

(B) Spectrum of posterior fossa abnormalities in the PACS2 cohort. Sagittal T1 weighted (m–p, u–x), axial T2 weighted (t, y–ab), axial T1 weighted (q, s), and coronal T2 weighted (r) imaging for subject 2 at 5 years of age (m, q), subject 4 at 3 weeks of age (n, r), subject 5 at 7 days of age (o, s), subject 9 at 1 week of age (p, t), subject 10 at 1 month of age (u, y), subject 12 at 3 months of age (v, z), subject 13 at 23 months of age (w, aa), and subject 14 at 2.5 years of age (x, ab). Of 8 subjects with centrally reviewed imaging, there was prominence of the cisterna magna (asterisk in o) in all but subject 13 (w) and widening of the foramen Magendie in all subjects except subject 12 (v). Mild inferior vermian hypoplasia was also evident in subjects 2 (m), 4 (n), 5 (o), and 14 (x). Cerebellar hemisphere dysplasia was present in subjects 2 (q), 4 (r), 5 (s), 12 (z), and 13 (aa) manifest as unusual centrifugal orientation of the folia bilaterally in subjects 2 (q, arrows) and 12 (z, arrows) and on the left side only in subject 5 (s, arrow). Distortion of the foliar pattern was present without centrifugal orientation in subjects 4 (r) and 13 (aa). Subtler foliar distortion was visible in subjects 9 (t) and 14 (ab).