2-170816868-G-A

Variant summary

Our verdict is Benign. Variant got -14 ACMG points: 0P and 14B. BP4_Strong BP6_Moderate BS1 BS2

The ENST00000375272.5(GAD1):c.-248G>A variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00335 in 158,256 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★).

• Frequency:
  • Genomes: 𝑓 0.0035 (5 hom., cov: 32)
  • Exomes 𝑓: 0.00031 (0 hom.)
• Consequence: GAD1 ENST00000375272.5 5_prime_UTR
• Clinical Significance: Benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.973

Genes affected

GAD1 (HGNC:4092): (glutamate decarboxylase 1) This gene encodes one of several forms of glutamic acid decarboxylase, identified as a major autoantigen in insulin-dependent diabetes. The enzyme encoded is responsible for catalyzing the production of gamma-aminobutyric acid from L-glutamic acid. A pathogenic role for this enzyme has been identified in the human pancreas since it has been identified as an autoantigen and an autoreactive T cell target in insulin-dependent diabetes. This gene may also play a role in the stiff man syndrome. Deficiency in this enzyme has been shown to lead to pyridoxine dependency with seizures. Alternative splicing of this gene results in two products, the predominant 67-kD form and a less-frequent 25-kD form. [provided by RefSeq, Jul 2008]

(HGNC:):

ACMG classification

Verdict is Benign. Variant got -14 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.61).
• BP6: Variant 2-170816868-G-A is Benign according to our data. Variant chr2-170816868-G-A is described in ClinVar as [Benign]. Clinvar id is 332215.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00348 (528/151720) while in subpopulation AFR AF= 0.0119 (492/41390). AF 95% confidence interval is 0.011. There are 5 homozygotes in gnomad4. There are 251 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd at 5 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GAD1	XM_011510922.1	c.-63-1661G>A		intron_variant
GAD1	NM_000817.3			upstream_gene_variant		ENST00000358196.8
GAD1	NM_013445.4			upstream_gene_variant
GAD1	XM_017003758.3			upstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
	ENST00000663207.1	n.324C>T		non_coding_transcript_exon_variant	1/2
GAD1	ENST00000358196.8			upstream_gene_variant		1	NM_000817.3	P1

Frequencies

GnomAD3 genomes AF: 0.00344 AC: 522 AN: 151602 Hom.: 5 Cov.: 32

Gnomad AFR AF: 0.0118

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00190

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000209

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00240

GnomAD4 exome AF: 0.000306 AC: 2 AN: 6536 Hom.: 0 Cov.: 0 AF XY: 0.000569 AC XY: 2 AN XY: 3514

Gnomad4 AFR exome AF: 0.0130

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00348 AC: 528 AN: 151720 Hom.: 5 Cov.: 32 AF XY: 0.00338 AC XY: 251 AN XY: 74200

Gnomad4 AFR AF: 0.0119

Gnomad4 AMR AF: 0.00190

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000209

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00238

Alfa AF: 0.00291 Hom.: 0

Bravo AF: 0.00388

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

Significance: Benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neurodevelopmental disorder with progressive spasticity and brain white matter abnormalities Benign:1

Benign, 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 and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.61
Cadd	Benign	15
Dann	Benign	0.93

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: rs576236119; hg19: chr2-171673378;