1-99851050-A-G

Position:

• chr1-99851050-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000642.3(AGL):​c.8A>G​(p.His3Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,260 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: AGL NM_000642.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.376

Genes affected

AGL (HGNC:321): (amylo-alpha-1, 6-glucosidase, 4-alpha-glucanotransferase) This gene encodes the glycogen debrancher enzyme which is involved in glycogen degradation. This enzyme has two independent catalytic activities which occur at different sites on the protein: a 4-alpha-glucotransferase activity and a amylo-1,6-glucosidase activity. Mutations in this gene are associated with glycogen storage disease although a wide range of enzymatic and clinical variability occurs which may be due to tissue-specific alternative splicing. Alternatively spliced transcripts encoding different isoforms have been described. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.10067421).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
AGL	NM_000642.3	c.8A>G	p.His3Arg	missense_variant	2/34	ENST00000361915.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
AGL	ENST00000361915.8	c.8A>G	p.His3Arg	missense_variant	2/34	1	NM_000642.3	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152260 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251434 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135898

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome Cov.: 33

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152260 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74390

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Glycogen storage disease type III Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 24, 2021

This sequence change replaces histidine with arginine at codon 3 of the AGL protein (p.His3Arg). The histidine residue is weakly conserved and there is a small physicochemical difference between histidine and arginine. This variant is present in population databases (rs752437446, ExAC 0.009%). This variant has not been reported in the literature in individuals with AGL-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The arginine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.062
BayesDel_addAF	Benign	-0.085	T
BayesDel_noAF	Benign	-0.36
CADD	Benign	14
DANN	Benign	0.93
DEOGEN2	Benign	0.047	T;T;T;T
Eigen	Benign	-0.52
Eigen_PC	Benign	-0.36
FATHMM_MKL	Benign	0.45	N
LIST_S2	Benign	0.69	T;.;.;.
M_CAP	Benign	0.011	T
MetaRNN	Benign	0.10	T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.98	L;L;L;L
MutationTaster	Benign	0.98	D;D;D;D;D
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-0.79	N;N;N;N
REVEL	Benign	0.034
Sift	Benign	0.32	T;T;T;T
Sift4G	Benign	0.49	T;T;T;T
Polyphen		0.0070	B;B;B;B
Vest4		0.15
MutPred		0.20		Gain of MoRF binding (P = 0.0158);Gain of MoRF binding (P = 0.0158);Gain of MoRF binding (P = 0.0158);Gain of MoRF binding (P = 0.0158);
MVP		0.65
MPC		0.047
ClinPred		0.11	T
GERP RS		2.8
Varity_R		0.097
gMVP		0.34

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs752437446; hg19: chr1-100316606;