12-120978769-A-G

Position:

• chr12-120978769-A-G

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2_Supporting PP4_Moderate PVS1

This summary comes from the ClinGen Evidence Repository: The c.1A>G variant in the HNF1 homeobox A gene, HNF1A, results in the loss of the initiation codon (p.Met1Val) of NM_000545.8. By altering the start codon of the coding sequence, this variant is predicted to cause a truncated or absent protein in a gene in which loss-of-function is an established disease mechanism (PVS1; PMID:23348805). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant was identified in an individual with a clinical history highly specific for HNF1A-MODY (MODY probability calculator result >50%, negative genetic testing for HNF4A, antibody negative) (PP4_Moderate; internal lab contributor). In summary, c.1A>G meets the criteria to be classified as pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.0, approved 9/30/2021): PVS1, PM2_Supporting, PP4_Moderate LINK:https://erepo.genome.network/evrepo/ui/classification/CA214292/MONDO:0015967/017

• Frequency: Genomes: not found (cov: 32)
• Consequence: HNF1A NM_000545.8 start_lost
• Clinical Significance: Pathogenic reviewed by expert panel P:5
• Conservation: PhyloP100: 7.33

Genes affected

HNF1A (HGNC:11621): (HNF1 homeobox A) The protein encoded by this gene is a transcription factor required for the expression of several liver-specific genes. The encoded protein functions as a homodimer and binds to the inverted palindrome 5'-GTTAATNATTAAC-3'. Defects in this gene are a cause of maturity onset diabetes of the young type 3 (MODY3) and also can result in the appearance of hepatic adenomas. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Apr 2015]

HNF1A-AS1 (HGNC:26785): (HNF1A antisense RNA 1)

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HNF1A	NM_000545.8	c.1A>G	p.Met1?	start_lost	1/10	ENST00000257555.11
HNF1A	NM_001306179.2	c.1A>G	p.Met1?	start_lost	1/10
HNF1A	NM_001406915.1	c.1A>G	p.Met1?	start_lost	1/9
HNF1A	XM_024449168.2	c.1A>G	p.Met1?	start_lost	1/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HNF1A	ENST00000257555.11	c.1A>G	p.Met1?	start_lost	1/10	1	NM_000545.8	P4
HNF1A-AS1	ENST00000619441.1	n.128+1875T>C		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Apr 03, 2023	This sequence change affects the initiator methionine of the HNF1A mRNA. The next in-frame methionine is located at codon 118. For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the HNF1A protein in which other variant(s) (p.Leu107Arg) have been determined to be pathogenic (PMID: 9166684). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 36814). This variant has not been reported in the literature in individuals affected with HNF1A-related conditions. This variant is not present in population databases (gnomAD no frequency). -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Oct 21, 2021	This variant results in the loss of the initiator methionine codon and is predicted to interfere with protein translation. If translation were to begin at the next methionine codon, p.Met118, the dimerization domain would be lost. This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). This variant has been identified in at least one individual with clinical features associated with this gene. Three different variants at this initiator codon have been reported in the literature. -

Maturity onset diabetes mellitus in young Pathogenic:1

Pathogenic, criteria provided, single submitter

research

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

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Mutations in HNF1A gene can predispose to MODY3. It is associated with both micro and macrovascular complications of diabetes, especially cardiovascular complications. Associated with glucosuria. May respond well to sulfonylureas. Sufficient evidence is found to confer the association of this particular variant rs193922592 with MODY3. -

Monogenic diabetes Pathogenic:1

Pathogenic, reviewed by expert panel

curation

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Mar 04, 2022

The c.1A>G variant in the HNF1 homeobox A gene, HNF1A, results in the loss of the initiation codon (p.Met1Val) of NM_000545.8. By altering the start codon of the coding sequence, this variant is predicted to cause a truncated or absent protein in a gene in which loss-of-function is an established disease mechanism (PVS1; PMID: 23348805). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant was identified in an individual with a clinical history highly specific for HNF1A-MODY (MODY probability calculator result >50%, negative genetic testing for HNF4A, antibody negative) (PP4_Moderate; internal lab contributor). In summary, c.1A>G meets the criteria to be classified as pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.0, approved 9/30/2021): PVS1, PM2_Supporting, PP4_Moderate -

Maturity-onset diabetes of the young type 3 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing;curation

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Aug 18, 2011

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Benign	22
DANN	Benign	0.94
DEOGEN2	Benign	0.40	.;T;T;T;T;.
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.90	D;D;D;D;D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D;D;D;D
PROVEAN	Benign	-2.3	N;.;.;N;N;N
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;.;.;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;D
Polyphen		0.81	.;.;.;.;.;P
Vest4		0.95
MutPred		0.83		Gain of ubiquitination at K4 (P = 0.1432);Gain of ubiquitination at K4 (P = 0.1432);Gain of ubiquitination at K4 (P = 0.1432);Gain of ubiquitination at K4 (P = 0.1432);Gain of ubiquitination at K4 (P = 0.1432);Gain of ubiquitination at K4 (P = 0.1432);
MVP		0.99
ClinPred		0.99	D
GERP RS		4.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
gMVP		0.73

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: rs193922592; hg19: chr12-121416572; COSMIC: COSV57463261;