rs80338738

Positions:

• chr15-45369325-C-A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PVS1 PP4 PM2_Supporting PM3_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_001482.3:c.484+1G>T variant in GATM occurs within the canonical splice donor site of intron 3. It was shown by RT-PCR to cause skipping of exon 3, resulting in a frameshift, premature termination codon, and nonsense-mediated decay (PMID:22386973) (PVS1). One individual who is homozygous for the variant has been reported with significantly decreased creatine peak on H1-MRS, nondetectable enzyme activity in cultured lymphoblasts, and low GAA in plasma and low creatine in plasma (PP4_Strong, PM3_Supporting). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00005 (1/18394) in the East Asian population, which is lower than the ClinGen CCDS VCEP's threshold for PM2_Supporting (<0.0004), meeting this criterion (PM2_Supporting). The variant is noted in ClinVar (Variation ID: 21299). In summary, this variant meets the criteria to be classified as pathogenic for AGAT deficiency. GATM-specific ACMG/AMP codes met, as specified by the ClinGen Cerebral Creatine Deficiency Syndromes VCEP (Specifications Version 1.1.0): PVS1, PP4_Strong, PM3_Supporting, PM2_Supporting.(Classification approved by the ClinGen CCDS VCEP on June 6, 2022). LINK:https://erepo.genome.network/evrepo/ui/classification/CA341869/MONDO:0012996/025

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GATM NM_001482.3 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:2
• Conservation: PhyloP100: 7.48

Genes affected

GATM (HGNC:4175): (glycine amidinotransferase) This gene encodes a mitochondrial enzyme that belongs to the amidinotransferase family. This enzyme is involved in creatine biosynthesis, whereby it catalyzes the transfer of a guanido group from L-arginine to glycine, resulting in guanidinoacetic acid, the immediate precursor of creatine. Mutations in this gene cause arginine:glycine amidinotransferase deficiency, an inborn error of creatine synthesis characterized by cognitive disability, language impairment, and behavioral disorders. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GATM	NM_001482.3	c.484+1G>T		splice_donor_variant		ENST00000396659.8	NP_001473.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GATM	ENST00000396659.8	c.484+1G>T		splice_donor_variant		1	NM_001482.3	ENSP00000379895	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251388 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135868

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460852 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726844

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: reviewed by expert panel

Submissions by phenotype

Arginine:glycine amidinotransferase deficiency Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	May 01, 2012	- -
Pathogenic, reviewed by expert panel	curation	ClinGen Cerebral Creatine Deficiency Syndromes Variant Curation Expert Panel, ClinGen	Jun 06, 2022	The NM_001482.3:c.484+1G>T variant in GATM occurs within the canonical splice donor site of intron 3. It was shown by RT-PCR to cause skipping of exon 3, resulting in a frameshift, premature termination codon, and nonsense-mediated decay (PMID: 22386973) (PVS1). One individual who is homozygous for the variant has been reported with significantly decreased creatine peak on H1-MRS, nondetectable enzyme activity in cultured lymphoblasts, and low GAA in plasma and low creatine in plasma (PP4_Strong, PM3_Supporting). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00005 (1/18394) in the East Asian population, which is lower than the ClinGen CCDS VCEP's threshold for PM2_Supporting (<0.0004), meeting this criterion (PM2_Supporting). The variant is noted in ClinVar (Variation ID: 21299). In summary, this variant meets the criteria to be classified as pathogenic for AGAT deficiency. GATM-specific ACMG/AMP codes met, as specified by the ClinGen Cerebral Creatine Deficiency Syndromes VCEP (Specifications Version 1.1.0): PVS1, PP4_Strong, PM3_Supporting, PM2_Supporting. (Classification approved by the ClinGen CCDS VCEP on June 6, 2022). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	A;A
GERP RS		5.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs80338738; hg19: chr15-45661523;