rs1057517952

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PM2PM4_SupportingPP5

The NM_013339.4(ALG6):​c.908_910del​(p.Cys303del) variant causes a inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000125 in 1,600,196 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000013 ( 0 hom. )

Consequence

ALG6
NM_013339.4 inframe_deletion

Scores

Not classified

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:2

Conservation

PhyloP100: 2.22
Variant links:
Genes affected
ALG6 (HGNC:23157): (ALG6 alpha-1,3-glucosyltransferase) This gene encodes a member of the ALG6/ALG8 glucosyltransferase family. The encoded protein catalyzes the addition of the first glucose residue to the growing lipid-linked oligosaccharide precursor of N-linked glycosylation. Mutations in this gene are associated with congenital disorders of glycosylation type Ic. [provided by RefSeq, Jul 2008]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM1
In a transmembrane_region Helical (size 20) in uniprot entity ALG6_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_013339.4
PM2
Very rare variant in population databases, with high coverage;
PM4
Nonframeshift variant in NON repetitive region in NM_013339.4. Strenght limited to Supporting due to length of the change: 1aa.
PP5
Variant 1-63415875-TTTG-T is Pathogenic according to our data. Variant chr1-63415875-TTTG-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 372732.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
ALG6NM_013339.4 linkuse as main transcriptc.908_910del p.Cys303del inframe_deletion 11/15 ENST00000263440.6

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
ALG6ENST00000263440.6 linkuse as main transcriptc.908_910del p.Cys303del inframe_deletion 11/155 NM_013339.4 P1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152178
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
0.0000131
AC:
19
AN:
1448018
Hom.:
0
AF XY:
0.0000166
AC XY:
12
AN XY:
721146
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000164
Gnomad4 OTH exome
AF:
0.0000167
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152178
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74352
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000147
Gnomad4 OTH
AF:
0.00
Bravo
AF:
0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:2
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Uncertain:2
Uncertain significance, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpMar 23, 2022Variant summary: ALG6 c.908_910delGTT (p.Cys303del) results in an in-frame deletion that is predicted to remove one amino acid from the encoded protein. The variant was absent in 249388 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.908_910delGTT has been reported in the literature as a presumed compound heterozygous genotype in at-least one individual affected with alpha-1,3-glucosyltransferase congenital disorder of glycosylation (ALG6-CDG) (example, Morava_2016) and also listed without a second allele or zygosity specified in a mutational update report (example, Haeuptle_2009). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory classified the variant as likely pathogenic and one laboratory classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, criteria provided, single submitterclinical testingGenetic Services Laboratory, University of ChicagoNov 16, 2015- -
not provided Pathogenic:1
Likely pathogenic, criteria provided, single submitterclinical testingGeneDxSep 23, 2016The c.908_910delGTT variant in the ALG6 gene has been previously reported in an least one individual with CDG who had a second variant, c.257+5G>A, although the phase for these two variants is unknown (Morava et al., 2016). The c.908_910delGTT variant causes an in-frame deletion of one amino acid, Cysteine 303, denoted p.C303del. This amino acid deletion occurs at a position that is not conserved across species. However, the c.908_910delGTT was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. We interpret c.908_910delGTT as a likely pathogenic variant. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.0
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs1057517952; hg19: chr1-63881546; API