12-120994321-C-G

Variant names:

• chr12-120994321-C-G
• rs151256267
• NM_000545.8:c.871C>G

Variant summary

Our verdict is Uncertain significance. The variant received -1 ACMG points: 4P and 5B. BP2 PS4_Moderate PM2_Supporting PP4 BS2

This summary comes from the ClinGen Evidence Repository: The c.871C>G variant in the HNF1 homeobox A gene, HNF1A, causes an amino acid change of proline to alanine at codon 291 (p.(Pro291Ala)) of NM_000545.8. This variant was identified in 4 unrelated individuals with non- autoimmune and non-absolute/near-absolute insulin-deficient diabetes (PS4_Moderate; internal lab contributors). Also, this variant has a minor allele frequency of 0.000009234 in the gnomAD v2.1.1 European non-Finnish population which is less than the ClinGen MDEP threshold for PM2_Supporting (≤0.00002 and ≤1 copy in any other subpopulation) (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) (PP4; internal lab contributors). Additionally, this variant was identified in a patient with different HNF1A variant curated by MDEP as pathogenic (BP2; internal lab contributors). This variant was identified in a normoglycemic individual >70 years old, and the expected penetrance for HNF1A-MODY is 95% by age 70 (BS2; internal lab contributors). This variant has a REVEL score of 0.28, which is between the ClinGen MDEP thresholds, predicting neither a damaging nor benign impact on HNF1A function. In summary, c.871C>G 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 1.1, approved 9/30/2021): PS4_Moderate, PM2_Supporting, PP4, BP5, BS2 LINK:https://erepo.genome.network/evrepo/ui/classification/CA244533124/MONDO:0007453/017

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: HNF1A NM_000545.8 missense
• Clinical Significance: Uncertain significance reviewed by expert panel U:4
• Conservation: PhyloP100: 0.661
• Publications: 15 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 -1 ACMG points.

• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.
• BP2: For more information check the summary or visit ClinGen Evidence Repository.
• BS2: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HNF1A	NM_000545.8	c.871C>G	p.Pro291Ala	missense_variant	Exon 4 of 10	ENST00000257555.11	NP_000536.6
HNF1A	NM_001306179.2	c.871C>G	p.Pro291Ala	missense_variant	Exon 4 of 10		NP_001293108.2
HNF1A	NM_001406915.1	c.871C>G	p.Pro291Ala	missense_variant	Exon 4 of 9		NP_001393844.1
HNF1A	XM_024449168.2	c.871C>G	p.Pro291Ala	missense_variant	Exon 4 of 9		XP_024304936.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HNF1A	ENST00000257555.11	c.871C>G	p.Pro291Ala	missense_variant	Exon 4 of 10	1	NM_000545.8	ENSP00000257555.5

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152216 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000417 AC: 1 AN: 239706 AF XY: 0.00000768

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000923

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1457718 Hom.: 0 Cov.: 35 AF XY: 0.0000138 AC XY: 10 AN XY: 724894

African (AFR) AF: 0.000209 AC: 7 AN: 33432

American (AMR) AF: 0.00 AC: 0 AN: 43876

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25892

East Asian (EAS) AF: 0.00 AC: 0 AN: 39606

South Asian (SAS) AF: 0.00 AC: 0 AN: 85634

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52904

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1110428

Other (OTH) AF: 0.0000332 AC: 2 AN: 60182

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152334 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74482

African (AFR) AF: 0.0000241 AC: 1 AN: 41572

American (AMR) AF: 0.0000653 AC: 1 AN: 15310

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.000207 AC: 1 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10628

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: reviewed by expert panel

Submissions by phenotype

not specified Uncertain:1

Jul 16, 2024

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HNF1A c.871C>G (p.Pro291Ala) results in a non-conservative amino acid change located in the Hepatocyte nuclear factor 1, beta isoform, C-terminal domain (IPR006897) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4.2e-06 in 239706 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.871C>G has been reported in the literature as heterozygous genotype in an individual affected with gestational diabetes (Daggag_2022). These report(s) do not provide unequivocal conclusions about association of the variant with Maturity Onset Diabetes Of The Young 3. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 36407475). ClinVar contains an entry for this variant (Variation ID: 1334146). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Diabetes mellitus type 1;C0011860:Type 2 diabetes mellitus;C1838100:Maturity-onset diabetes of the young type 3;C1840646:Hepatic adenomas, familial;C2675866:Type 1 diabetes mellitus 20;CN074294:Nonpapillary renal cell carcinoma Uncertain:1

Dec 21, 2023

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Monogenic diabetes Uncertain:1

Jan 03, 2022

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The c.871C>G variant in the HNF1 homeobox A gene, HNF1A, causes an amino acid change of proline to alanine at codon 291 (p.(Pro291Ala)) of NM_000545.8. This variant was identified in 4 unrelated individuals with non- autoimmune and non-absolute/near-absolute insulin-deficient diabetes (PS4_Moderate; internal lab contributors). Also, this variant has a minor allele frequency of 0.000009234 in the gnomAD v2.1.1 European non-Finnish population which is less than the ClinGen MDEP threshold for PM2_Supporting (≤0.00002 and ≤1 copy in any other subpopulation) (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) (PP4; internal lab contributors). Additionally, this variant was identified in a patient with different HNF1A variant curated by MDEP as pathogenic (BP2; internal lab contributors). This variant was identified in a normoglycemic individual >70 years old, and the expected penetrance for HNF1A-MODY is 95% by age 70 (BS2; internal lab contributors). This variant has a REVEL score of 0.28, which is between the ClinGen MDEP thresholds, predicting neither a damaging nor benign impact on HNF1A function. In summary, c.871C>G 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 1.1, approved 6/4/2021): PS4_Moderate, PM2_Supporting, PP4, BP5, BS2 -

not provided Uncertain:1

Aug 28, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline with alanine at codon 291 of the HNF1A protein (p.Pro291Ala). The proline residue is moderately conserved and there is a small physicochemical difference between proline and alanine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with HNF1A-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt HNF1A protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.049
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Benign	6.1
DANN	Benign	0.93
DEOGEN2	Uncertain	0.45	.;T;T;.
Eigen	Benign	-0.88
Eigen_PC	Benign	-0.91
FATHMM_MKL	Benign	0.26	N
LIST_S2	Benign	0.76	T;T;T;T
M_CAP	Pathogenic	0.31	D
MetaRNN	Benign	0.21	T;T;T;T
MetaSVM	Uncertain	0.025	D
PhyloP100		0.66
PrimateAI	Benign	0.47	T
PROVEAN	Benign	-0.60	N;.;N;N
REVEL	Benign	0.28
Sift	Benign	0.039	D;.;D;D
Sift4G	Benign	0.40	T;T;T;T
Polyphen		0.0060	.;.;.;B
Vest4		0.43
MutPred		0.51		Loss of glycosylation at P291 (P = 0.0054);Loss of glycosylation at P291 (P = 0.0054);Loss of glycosylation at P291 (P = 0.0054);Loss of glycosylation at P291 (P = 0.0054);
MVP		0.70
MPC		0.13
ClinPred		0.091	T
GERP RS		1.6
gMVP		0.45
Mutation Taster		=22/78	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: rs151256267; hg19: chr12-121432124;