22-49903484-C-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BS1_Supporting

The NM_024105.4(ALG12):c.*354G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000106 in 491,194 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00014 (1 hom.)
• Consequence: ALG12 NM_024105.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -3.66

Genes affected

ALG12 (HGNC:19358): (ALG12 alpha-1,6-mannosyltransferase) This gene encodes a member of the glycosyltransferase 22 family. The encoded protein catalyzes the addition of the eighth mannose residue in an alpha-1,6 linkage onto the dolichol-PP-oligosaccharide precursor (dolichol-PP-Man(7)GlcNAc(2)) required for protein glycosylation. Mutations in this gene have been associated with congenital disorder of glycosylation type Ig (CDG-Ig)characterized by abnormal N-glycosylation. [provided by RefSeq, Jul 2008]

(HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.96).
• BS1: Variant frequency is greater than expected in population mid. gnomad4_exome allele frequency = 0.000145 (49/338882) while in subpopulation MID AF= 0.0134 (40/2984). AF 95% confidence interval is 0.0101. There are 1 homozygotes in gnomad4_exome. There are 27 alleles in male gnomad4_exome subpopulation. Median coverage is 0. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALG12	NM_024105.4	c.*354G>A		3_prime_UTR_variant	10/10	ENST00000330817.11
ALG12	XM_017028936.2	c.1238+695G>A		intron_variant
ALG12	XM_017028937.2	c.1238+695G>A		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALG12	ENST00000330817.11	c.*354G>A		3_prime_UTR_variant	10/10	1	NM_024105.4	P1
	ENST00000610245.1	n.1257C>T		non_coding_transcript_exon_variant	1/1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152194 Hom.: 0 Cov.: 33

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: 0.00633

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000289 AC: 4 AN: 138406 Hom.: 0 AF XY: 0.0000266 AC XY: 2 AN XY: 75090

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.000121

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000889

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000179

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000145 AC: 49 AN: 338882 Hom.: 1 Cov.: 0 AF XY: 0.000142 AC XY: 27 AN XY: 190510

Gnomad4 AFR exome AF: 0.0000985

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000846

Gnomad4 SAS exome AF: 0.0000333

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000165

Gnomad4 OTH exome AF: 0.000121

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152312 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74458

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

Alfa AF: 0.0000868 Hom.: 0

Bravo AF: 0.0000189

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

ALG12-congenital disorder of glycosylation Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.96
Cadd	Benign	0.17
Dann	Benign	0.45
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

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

Other links and lift over

dbSNP: rs769523769; hg19: chr22-50297132;