22-24610357-G-A

Position:

• chr22-24610357-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The ENST00000400380.5(GGT1):​c.-181-1G>A variant causes a splice acceptor change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 31)
• Consequence: GGT1 ENST00000400380.5 splice_acceptor
• Scores: Splicing: ADA: 0.9998
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.29

Genes affected

GGT1 (HGNC:4250): (gamma-glutamyltransferase 1) The enzyme encoded by this gene is a type I gamma-glutamyltransferase that catalyzes the transfer of the glutamyl moiety of glutathione to a variety of amino acids and dipeptide acceptors. The enzyme is composed of a heavy chain and a light chain, which are derived from a single precursor protein. It is expressed in tissues involved in absorption and secretion and may contribute to the etiology of diabetes and other metabolic disorders. Multiple alternatively spliced variants have been identified. There are a number of related genes present on chromosomes 20 and 22, and putative pseudogenes for this gene on chromosomes 2, 13, and 22. [provided by RefSeq, Jan 2014]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.10116959 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.9, offset of 1, new splice context is: aacctcccttgaccttcaAGaga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GGT1	NM_001288833.2	c.-182G>A		5_prime_UTR_variant	4/16	ENST00000400382.6	NP_001275762.1
GGT1	NM_013421.3	c.-181-1G>A		splice_acceptor_variant			NP_038265.2
GGT1	NM_013430.3	c.-182G>A		5_prime_UTR_variant	4/16		NP_038347.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GGT1	ENST00000400382.6	c.-182G>A		5_prime_UTR_variant	4/16	2	NM_001288833.2	ENSP00000383232	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	21
DANN	Benign	0.79

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.75
SpliceAI score (max)		0.13		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: rs3966262; hg19: chr22-25006324;