NM_000545.8:c.794A>C

Variant names:

• chr12-120994244-A-C
• rs1555212006
• NM_000545.8:c.794A>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2_Supporting PP3 PM1

This summary comes from the ClinGen Evidence Repository: The c.794A>C variant in the HNF1 homeobox A gene, HNF1A, causes an amino acid change of tyrosine to serine at codon 265 (p.Tyr265Ser) of NM_000545.8. This variant resides in an amino acid within the HNF1α DNA binding domain that directly binds DNA, which is defined as critical for the protein’s function by the ClinGen MDEP (PM1). Also, this variant is absent from gnomAD v4.1.0 (PM2_Supporting). This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.938, which is greater than the MDEP VCEP threshold of 0.70 (PP3). Another missense variant, c.794A>G (p.Tyr265Cys), has been classified as a VUS by the ClinGen MDEP; therefore, PM5 will not be applied. In summary, c.794A>C meets the criteria to be classified as a variant of uncertain significance for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 3.0.0, approved 6/30/2025): PM1, PM2_Supporting, PP3 LINK:https://erepo.genome.network/evrepo/ui/classification/CA386966192/MONDO:0015967/017

• Frequency: Genomes: not found (cov: 32)
• Consequence: HNF1A NM_000545.8 missense
• Clinical Significance: Uncertain significance reviewed by expert panel P:1 U:4
• Conservation: PhyloP100: 8.86
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• monogenic diabetes

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• type 1 diabetes mellitus 20

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Laboratory for Molecular Medicine, Genomics England PanelApp
• diabetes mellitus, noninsulin-dependent

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• maturity-onset diabetes of the young type 3

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• hyperinsulinism due to HNF1A deficiency

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• maturity-onset diabetes of the young

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• nonpapillary renal cell carcinoma

  Inheritance: Unknown Classification: NO_KNOWN Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000545.8. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HNF1A	NM_000545.8	MANE Select	c.794A>C	p.Tyr265Ser	missense	Exon 4 of 10	NP_000536.6
	HNF1A	NM_001306179.2		c.794A>C	p.Tyr265Ser	missense	Exon 4 of 10	NP_001293108.2
	HNF1A	NM_001406915.1		c.794A>C	p.Tyr265Ser	missense	Exon 4 of 9	NP_001393844.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HNF1A	ENST00000257555.11	TSL:1 MANE Select	c.794A>C	p.Tyr265Ser	missense	Exon 4 of 10	ENSP00000257555.5
	HNF1A	ENST00000544413.2	TSL:1	c.794A>C	p.Tyr265Ser	missense	Exon 4 of 10	ENSP00000438804.1
	HNF1A	ENST00000538646.5	TSL:1	n.607A>C		non_coding_transcript_exon	Exon 3 of 6	ENSP00000443964.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
-	2	-	not specified (2)
1	-	-	Maturity onset diabetes mellitus in young (1)
-	1	-	Monogenic diabetes (1)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D
Eigen	Pathogenic	0.70
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.0	D
PhyloP100		8.9
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-6.7	D
REVEL	Pathogenic	0.94
Sift	Benign	0.034	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.90
MutPred		0.69		Gain of disorder (P = 0.0209)
MVP		0.98
MPC		2.5
ClinPred		1.0	D
GERP RS		4.8
gMVP		0.99
Mutation Taster		=0/100	disease causing

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

Other links and lift over

dbSNP: rs1555212006; hg19: chr12-121432047;