12-120997504-C-T

Variant names:

• chr12-120997504-C-T
• rs137853236
• NM_000545.8:c.1340C>T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PS4 PP1_Strong PS2_Supporting PP4 PP3 PM2_Supporting PS3_Moderate

This summary comes from the ClinGen Evidence Repository: The c.1340C>T variant in the HNF1 homeobox A gene, HNF1A, causes an amino acid change of proline to leucine at codon 447 (p.(Pro447Leu)) of NM_000545.8. This variant was identified as a de novo occurrence with unconfirmed parental relationships in an individual with diabetes, but whose clinical picture is not highly specific for HNF1A-MODY ([MODY probability calculator result <50%/HNF4A not tested) (PS2_Supporting; internal lab contributors). A luciferase assay meeting the ClinGen MDEP quality control specifications demonstrated that the p.Pro447Leu protein has transactivation activity below 40% of wildtype, indicating that this variant impacts protein function (PS3_Moderate, PMIDs: 27899486, 12530534, 10585442, 32910913, 32910913). This variant was identified in 11 unrelated individuals with non- autoimmune and non-absolute/near-absolute insulin-deficient diabetes (PS4; internal lab contributors) and is absent from gnomAD v2.1.1 (PM2_Supporting). This variant segregated with diabetes, with at least 15 informative meioses in families with MODY (PP1_Strong; internal lab contributors), and is predicted to be deleterious by computational evidence, with a REVEL score of 0.957, which is greater than or equal to the MDEP VCEP threshold of 0.70 (PP3). Lastly, this variant was identified in at least two individuals with a clinical history highly specific for HNF1A-MODY (MODY probability calculator result >50%, negative genetic testing for HNF4A) (PP4; internal lab contributors). In summary, c.1340C>T meets the criteria to be classified as pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.1, approved 6/4/2021): PS4, PP1_Strong, PP3, PP4, PS2_Supporting, PM2_Supporting, PS3_Moderate. LINK:https://erepo.genome.network/evrepo/ui/classification/CA124454/MONDO:0015967/017

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: HNF1A NM_000545.8 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:8
• Conservation: PhyloP100: 7.90

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]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PS2: For more information check the summary or visit ClinGen Evidence Repository.
• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP1: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: 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.1340C>T	p.Pro447Leu	missense_variant	Exon 7 of 10	ENST00000257555.11	NP_000536.6
HNF1A	NM_001306179.2	c.1340C>T	p.Pro447Leu	missense_variant	Exon 7 of 10		NP_001293108.2
HNF1A	XM_024449168.2	c.1340C>T	p.Pro447Leu	missense_variant	Exon 7 of 9		XP_024304936.1
HNF1A	NM_001406915.1	c.1309+762C>T		intron_variant	Intron 6 of 8		NP_001393844.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HNF1A	ENST00000257555.11	c.1340C>T	p.Pro447Leu	missense_variant	Exon 7 of 10	1	NM_000545.8	ENSP00000257555.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000120 AC: 3 AN: 249186 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 134986

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000480

Gnomad NFE exome AF: 0.0000177

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1459660 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 726138

Gnomad4 AFR exome AF: 0.00

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:3

Apr 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 447 of the HNF1A protein (p.Pro447Leu). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with maturity-onset diabetes of the young (PMID: 8945470). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 14928). 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 with a negative predictive value of 80%. Experimental studies have shown that this missense change affects HNF1A function (PMID: 12530534). For these reasons, this variant has been classified as Pathogenic. -

Sep 12, 2022

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The frequency of this variant in the general population is consistent with pathogenicity (Genome Aggregation Database (gnomAD), Cambridge, MA (URL: http://gnomad.broadinstitute.org)). This variant segregates with disease in multiple families. Assessment of experimental evidence suggests this variant results in abnormal protein function. Studies showed reduction in transcription activity (PMID: 24915262, 10585442, 12530534). -

Oct 20, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Published functional studies demonstrate a damaging effect: loss of trans-activation activity and dominant negative effect (Vaxillaire et al., 1999; Najmi et al., 2016); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 20393147, 16496320, 11058894, 24915262, 29207974, 34496959, 12530534, 26646800, 30121369, 12574234, 28701371, 21224407, 17937063, 17573900, 29927023, 18838325, 11296231, 8945470, 9075819, 32041611, 10585442, 27899486, 36227502) -

Maturity onset diabetes mellitus in young Pathogenic:2

May 26, 2021

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HNF1A c.1340C>T (p.Pro447Leu) results in a non-conservative amino acid change located in the C-terminal domain (IPR006897) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 249186 control chromosomes (gnomAD). c.1340C>T has been reported in the literature in multiple individuals affected with or suspected of Maturity Onset Diabetes of the Young 3 (example: Yamagata_1996, Estalella_2007. Yorifuji_2018) . These data indicate that the variant is very likely to be associated with disease. In in vitro functional studies, the variant was found to have reduced DNA binding and transcriptional activity (example: Thomas_2002, Najmi_2017). Two ClinVar submitters (evaluation after 2014) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

-

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

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 rs137853236 with MODY3. -

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 Pathogenic:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Monogenic diabetes Pathogenic:1

Dec 31, 2021

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The c.1340C>T variant in the HNF1 homeobox A gene, HNF1A, causes an amino acid change of proline to leucine at codon 447 (p.(Pro447Leu)) of NM_000545.8. This variant was identified as a de novo occurrence with unconfirmed parental relationships in an individual with diabetes, but whose clinical picture is not highly specific for HNF1A-MODY ([MODY probability calculator result <50%/HNF4A not tested) (PS2_Supporting; internal lab contributors). A luciferase assay meeting the ClinGen MDEP quality control specifications demonstrated that the p.Pro447Leu protein has transactivation activity below 40% of wildtype, indicating that this variant impacts protein function (PS3_Moderate, PMIDs: 27899486, 12530534, 10585442, 32910913, 32910913). This variant was identified in 11 unrelated individuals with non- autoimmune and non-absolute/near-absolute insulin-deficient diabetes (PS4; internal lab contributors) and is absent from gnomAD v2.1.1 (PM2_Supporting). This variant segregated with diabetes, with at least 15 informative meioses in families with MODY (PP1_Strong; internal lab contributors), and is predicted to be deleterious by computational evidence, with a REVEL score of 0.957, which is greater than or equal to the MDEP VCEP threshold of 0.70 (PP3). Lastly, this variant was identified in at least two individuals with a clinical history highly specific for HNF1A-MODY (MODY probability calculator result >50%, negative genetic testing for HNF4A) (PP4; internal lab contributors). In summary, c.1340C>T meets the criteria to be classified as pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.1, approved 6/4/2021): PS4, PP1_Strong, PP3, PP4, PS2_Supporting, PM2_Supporting, PS3_Moderate. -

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

Apr 01, 1997

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	.;D;D;.;D;.
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D;D;D;D;D;D
M_CAP	Pathogenic	0.43	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-5.6	D;.;.;.;D;D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;.;.;.;D;D
Sift4G	Uncertain	0.0020	D;D;D;D;D;D
Polyphen		1.0	.;.;.;.;.;D
Vest4		0.99
MutPred		0.91		Gain of catalytic residue at P447 (P = 0.0116);Gain of catalytic residue at P447 (P = 0.0116);.;.;Gain of catalytic residue at P447 (P = 0.0116);Gain of catalytic residue at P447 (P = 0.0116);
MVP		1.0
MPC		0.56
ClinPred		0.99	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs137853236; hg19: chr12-121435307; COSMIC: COSV57460124; COSMIC: COSV57460124;