Classification<unk>  is classified as follows: Type OMIM Gene Locus Distinctive features Alternate names<unk> 1A VRK1 14q32 Infantile onset anterior horn cell degeneration resulting in progressive muscle atrophy; resembles infantile spinal muscular atrophy Spinal muscular atrophy with<unk>  (SMA-PCH)<unk> 1B EXOSC3 9p13.2 Cerebellar and spinal motor neuron degeneration beginning at birth and resulting in decreased body tone, respiratory insufficiency, muscle atrophy, progressive microcephaly and global developmental delay<unk> 2A TSEN54 17q25.1 Dyskinetic movements, seizures (frequently) Volendam neurodegenerative disease<unk> 2B TSEN2 3p25.2<unk> 2C TSEN34 19q13.42<unk> 2D SEPSECS 4p15.2 Progressive cerebello-cerebral atrophy (PCCA)<unk> 2E VPS53 17p13.3 Profound mental retardation, progressive microcephaly, spasticity, and early-onset epilepsy<unk> 2F TSEN15 1q25.3 Variable neurologic signs and symptoms, including cognitive and motor delay, poor or absent speech, seizures, and spasticity<unk> 3 PCLO 7q11–q21 Seizures, short stature, optic atrophy, progressive microcephaly, severe developmental delay; described only in a handful of cases. CLAM-PCH, cerebellar atrophy with progressive microcephaly<unk> 4 TSEN54 17q25.1 Severe prenatal form of<unk> 2 with excess fluid in the amniotic sac, muscle contractures, brief involuntary muscle twitching, brief episodes without breathing, and early death following birth<unk> 5 TSEN54 17q25.1 Severe prenatal form, described in one family Olivopontocerebellar<unk>  (OPCH)<unk> 6 RARS2 6q15 Severe encephalopathy in the newborn with hypotonia, and inconstantly: intractable seizures, edema, increased lactate blood levels, mitochondrial respiratory chain defects<unk> 7 TOE1 1p34.1 Hypotonia, apneic episodes, seizures, vanishing testis<unk> 8 CHMP1A 16q24.3 Severe psychomotor retardation, abnormal movements, hypotonia, spasticity, and variable visual defects<unk> 9 AMPD2 1p13.3 Severely delayed psychomotor development, progressive microcephaly, spasticity, seizures, and brain abnormalities, including brain atrophy, thin corpus callosum, and delayed myelination<unk> 10 CLP1 11q12.1 Severely delayed psychomotor development, progressive microcephaly, spasticity, seizures, and brain abnormalities, including brain atrophy and delayed myelination Pontine and cerebellar<unk>  is also observed in certain phenotypes of X-linked mental retardation – so called MICPCH. Another gene that has been associated with this condition is coenzyme A synthase (COASY).
Pontocerebellar hypoplasia
Cerebellar hypoplasia
Cerebellar agenesis
Olivopontocerebellar atrophy
Athetoid cerebral palsy
Acrocallosal syndrome
Ataxic cerebral palsy
Infantile progressive bulbar palsy