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Intellectual disability

Gene: FBXO28

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FBXO28 (F-box protein 28)
EnsemblGeneIds (GRCh38): ENSG00000143756
EnsemblGeneIds (GRCh37): ENSG00000143756
OMIM: 609100, Gene2Phenotype
FBXO28 is in 2 panels

1 review

Konstantinos Varvagiannis (Other)

Green List (high evidence)

Heterozygous pathogenic FBXO28 variants cause Developmental and epileptic encephalopathy 100 (# 619777).

At least 10 individuals with monoallelic missense / truncating FBXO28 variants have been reported. The subject with de novo frameshift variant initially reported by Balak et al (2018 - PMID:30160831) was included with additional clinical details in a recent report along with 9 further individuals (Schneider et al, 2021 - PMID: 33280099).

The phenotype corresponds to a developmental and epileptic encephalopathy with severe/profound ID. As discussed by Schneider et al, all individuals had DD prior to seizure onset which occurred at a median age of 22.5 months (range: 8m - 5y). The authors noted that missense variants may be associated with a milder phenotype (e.g. seizures occurred at the age of 4-5 years in 3 individuals).

Given these, FBXO28 appears to be relevant for inclusion in the current panel, with investigations prior to seizure onset.

As in the summary by Schneider et al, the gene encodes F-box only protein 28, a ubiquitin ligase promoting ubiquitination and degradation of phosphorylated proteins.

While FBXO28 has been suggested to have a critical role in 1q41q42 deletions (most spanning also WDR26) the authors note that a mechanism different than haploinsufficiency may underly FBXO28 encephalopathy.

Importantly, all 5 truncating variants reported (and 2/4 missense ones) occurred in the last exon, making these variants less susceptible to NMD. 2 other (of the 4) missense variants clustered in the F-box domain, which the authors hypothesize may correspond to a second pathogenic region.

7/9 variants arose de novo while 2 individuals had inherited a missense and a stopgain variant from mosaic unaffected parents (2.5% and 6%).

A comparison of the FBXO28-associated phenotype with the respective of 1q41q42 deletions and WDR26-related NDD is also made.

Consider inclusion in the ID panel with green (or amber) rating. Please consider inclusion in other possibly relevant panels (e.g. microcephaly (4/10), movement disorders, etc).
Sources: Literature
Created: 25 Apr 2022, 12:57 p.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Phenotypes
Developmental and epileptic encephalopathy 100 (# 619777)

Publications

Details

Mode of Inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Sources
Phenotypes
  • Developmental and epileptic encephalopathy 100 (# 619777)
OMIM
609100
Clinvar variants
Variants in FBXO28
Penetrance
unknown
Publications
Panels with this gene

History Filter Activity

25 Apr 2022, Gel status: 0

Created, Added New Source, Set mode of inheritance, Set publications, Set Phenotypes, Set penetrance

Konstantinos Varvagiannis (Other)

gene: FBXO28 was added gene: FBXO28 was added to Intellectual disability. Sources: Literature Mode of inheritance for gene: FBXO28 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: FBXO28 were set to 30160831; 33280099 Phenotypes for gene: FBXO28 were set to Developmental and epileptic encephalopathy 100 (# 619777) Penetrance for gene: FBXO28 were set to unknown Review for gene: FBXO28 was set to GREEN