Mobius syndrome , HGPPS

1. Mobius syndrome
Congenital hypoplastic or absence of CN VI and CN VII nuclei with resultant flattening of floor of 4th
ventricle and tent-shaped ventricle.

2. HGPPS
- Hypoplastic basis pontis (basal/basilar part
of the pons), pontine tegmentum (dorsal
pons), cerebellar peduncles and abducens
nuclei.
- absence of decussation of the superior
cerebellar peduncle resulting in a deep
midline posterior pontine cleft- “split Pons
sign”, sometimes described as “tent-shaped”
- MLF likely involved due to lack of
decussation at pons level.
- There is also association of uncrossed
bilateral corticospinal tracts . Agenesis of the
pontocerebellar tracts and afferent fibers
within the inferior cerebellar peduncles-
contributes to progressive scoliosis.