Congenital disorders of glycosylation
Gene: FUT8GlyGen link updated April 2021: https://www.glygen.org/protein/Q9BYC5-1#DiseaseCreated: 8 Apr 2021, 12:28 p.m. | Last Modified: 8 Apr 2021, 12:28 p.m.
Panel Version: 2.66
Comment on list classification: New gene added by external expert and reviewed by curation team, enough evidence to support gene-disease association and relevance to this panel to rate this gene GreenCreated: 19 Nov 2018, 1:24 p.m.
PMID: 29304374 reports on 3 unrelated individuals with biallelic pathogenic variants in FUT8.
Two of the patients were born to consanguineous parents and were found to be homozygous for stopgain variants (p.Arg239* in one family and p.Arg315* in the other). A third patient was compound heterozygous for a missense as well as a splice variant.
All three presented with similar phenotype consisting of polyhydramnios (2 out of 3), IUGR and failure to thrive with short stature (3/3), severe developmental delay (3/3) with microcephaly (3/3) and seizures (3/3). Variable respiratory problems were also noted in all.
Western blot demonstrated loss of FUT8 protein expression in one individual homozygous for a stopgain mutation as well as the patient who was compound heterozygous for the missense and the splice variant. The splice variant was further shown to produce a shorter transcript due to lack of exon 9, leading to an in-frame deletion of 59 residues critical for the protein function.
Additional studies confirmed the fucosylation defect compared to controls.
The authors note that while Fut8 knockout mice are born normal, 70% die within the first 3 days due to severe growth retardation and respiratory deficiency (similarly to what is observed in humans, though to a lesser extent).
This type of CDG is associated with a normal carbohydrate-deficient transferrin (CDT) pattern.
As a result this gene can be considered for inclusion in this panel probably as green.
Sources: LiteratureCreated: 17 Nov 2018, 7:56 p.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Congenital disorder of glycosylation with defective fucosylation, 618005
Publications
Gene: fut8 has been classified as Green List (High Evidence).
gene: FUT8 was added gene: FUT8 was added to Congenital disorders of glycosylation. Sources: Literature Mode of inheritance for gene: FUT8 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: FUT8 were set to 29304374 Phenotypes for gene: FUT8 were set to Congenital disorder of glycosylation with defective fucosylation, 618005 Penetrance for gene: FUT8 were set to Complete Review for gene: FUT8 was set to GREEN