| PCH2 |
277470, 612389, 612390 |
Neonatal period: clonus, impaired swallowing.
Infancy and later: chorea, variable spastic pareses; progressive microcephaly.
MRI: variable neocortical atrophy, pontocerebellar hypoplasia. |
Infancy and childhood. Adolescence reached in some cases |
Cerebellar hypoplasia: hemispheres≫vermis. Segmental degeneration of cortex. Fragmentation of cerebellar dentate nucleus.
Olivary nucleus: neuron loss and decreased folding.
Pons: progressive loss of ventral nuclei and transverse fibers. |
TSEN54, p.A307S/A307S most common.
Rarely: Other TSEN54 missense mutations. TSEN2, TSEN34 mutations. |
Barth et al10; Steinlin et al11; Barth et al8; Budde et al3; Namavar et al1
|
| PCH4 |
225753 |
Neonatal period: hypertonia, severe clonus, polyhydramnios and/or contractures; primary hypoventilation.
MRI: delayed neocortical maturation, pontocerebellar hypoplasia; micrencephaly on autopsy. |
Early postnatal death from apnea |
Cerebellar hypoplasia: hemispheres≫vermis, areas of stunted or absent folial development. Cerebellar dentate nucleus present as tiny remnants.
Olivary nucleus: absent folding and gliosis.
Pons: loss of ventral nuclei and transverse fibers. |
TSEN54
Compound heterozygosity for p.A307S plus nonsense or splice site mutations. |
Albrecht et al7; Chaves-Vischer et al9; Barth et al8; Budde et al3; Namavar et al1
|
| PCH5 |
611523 |
Prenatal/neonatal period: clonus or seizures.
Neonatal period: persistent clonus; micrencephaly and pontocerebellar hypoplasia on autopsy. |
Early postnatal death from apnea |
Cerebellar hypoplasia: cortical involvement as in PCH4, but vermal cortex more extensively affected than hemispheric cortex; subtotal loss of cerebellar dentate nucleus.
Olivary nucleus: absent folding.
Pons: loss of ventral nuclei and transverse fibers. |
TSEN54
Compound heterozygosity for p.A307S plus splice site mutation. |
Patel et al6, this paper |
