Cerebellar and Pontocerebellar Hypoplasia

Gene: VPS4A

Green List (high evidence)

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
CIMDAG syndrome MIM# 619273

Mode of pathogenicity
Other

Comment on mode of pathogenicity: Dominant negative

Created: 7 Dec 2020, 5:22 a.m. | Last Modified: 7 Dec 2020, 5:22 a.m.

Panel Version: 0.158

Comment when marking as ready: PMID: 33186543 - 2x de novo hetorozygous missense variants in the AAA (large ATPase) domain. 1x homozygous missense in the MIT domain (milder phenotype and unaffected parents - possibly just a simple LoF mechanism for AR inheritance). Demonstrated defective CD71 trafficking in all 3 patients.

PMID: 33186545 - 6x probands with de novo missense variants in the AAA domain. 5 of the variants were at amino acid position 284 (changes to Trp and Gly). Demonstrated that the variants had a dominant-negative effect on VPS4A function. "The six probands with de novo substitutions affecting Glu206 or Arg284 had a consistent phenotype characterized by severe DD, profound ID, and dystonia. Children were very delayed in establishing head control and none achieved independent walking. Other common findings were cerebellar hypoplasia (five individuals out of six, the other showing uncharacterized severe cerebral atrophy) with a variable degree of corpus callosum hypoplasia. One individual also had bilateral polymicrogyria. Epilepsy was present in three and dystonia in five subjects. Eye involvement was also a common finding, including congenital cataract, retinal dystrophy, and in one case congenital Leber amaurosis. Four individuals were diagnosed with hepatosplenomegaly and/or steatosis. Three subjects had anemia, which was characterized as dyserythropoietic in two. Severe feeding difficulties were present in four individuals, requiring assisted feeding in three. Two had sensorineural deafness. Severe growth retardation, generally for all parameters, was present in most cases. Notably, severe microcephaly (typically with Z scores < −5) was universal. Overall, the disorder seems to have a poor prognosis as two affected individuals died in childhood or early adult life."

Created: 7 Dec 2020, 5:21 a.m. | Last Modified: 7 Dec 2020, 5:22 a.m.

Panel Version: 0.158

Green List (high evidence)

PMID: 33186543 - 2x de novo hetorozygous missense variants in the AAA (large ATPase) domain.
1x homozygous missense in the MIT domain (milder phenotype and unaffected parents - possibly just a simple LoF mechanism for AR inheritance).
Demonstrated defective CD71 trafficking in all 3 patients.

PMID: 33186545 - 6x probands with de novo missense variants in the AAA domain. 5 of the variants were at amino acid position 284 (changes to Trp and Gly).
Demonstrated that the variants had a dominant-negative effect on VPS4A function.

"The six probands with de novo substitutions affecting Glu206 or Arg284 had a consistent phenotype characterized by severe DD, profound ID, and dystonia. Children were very delayed in establishing head control and none achieved independent walking. Other common findings were cerebellar hypoplasia (five individuals out of six, the other showing uncharacterized severe cerebral atrophy) with a variable degree of corpus callosum hypoplasia. One individual also had bilateral polymicrogyria. Epilepsy was present in three and dystonia in five subjects. Eye involvement was also a common finding, including congenital cataract, retinal dystrophy, and in one case congenital Leber amaurosis. Four individuals were diagnosed with hepatosplenomegaly and/or steatosis. Three subjects had anemia, which was characterized as dyserythropoietic in two. Severe feeding difficulties were present in four individuals, requiring assisted feeding in three. Two had sensorineural deafness. Severe growth retardation, generally for all parameters, was present in most cases. Notably, severe microcephaly (typically with Z scores < −5) was universal. Overall, the disorder seems to have a poor prognosis as two affected individuals died in childhood or early adult life."
Sources: Literature

Created: 7 Dec 2020, 5:13 a.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
Neurodevelopmental disorder

Publications

• 33186543
• 33186545