rs137853237

Positions:

• chr12-120988871-A-G
• chr12-120988871-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1_Supporting PS3_Supporting PP1_Moderate PP3 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The c.395A>G variant in the HNF1 homeobox A gene, HNF1A, causes an amino acid change of tyrosine to cysteine at codon 122 (p.(Y122C)) of NM_000545.8. This variant is located within the DNA binding domain (codons 107-174) of HNF1A, which is defined as critical for the protein’s function by the ClinGen MDEP (PM1_Supporting). This variant is also predicted to be deleterious by computational evidence, with a REVEL score of 0.977, which is greater than the MDEP threshold of 0.70 (PP3). This variant is absent from gnomAD v2.1.1 (PM2_Supporting) and was identified in two individuals with diabetes; however, the MODY probability is unable to be calculated due to lack of clinical information (PMID:9097962, internal lab contributor). The variant also segregated with diabetes with four informative meioses in one family with MODY (PP1_Moderate; PMID:9097962). Additionally, functional studies demonstrated the p.Tyr122Cys protein has DNA binding and transactivation below 40% of wild type, indicating that this variant impacts protein function (PMID:10585442). Another missense variant, c.364T>C (p.Tyr122His) has been classified as a VUS by the ClinGen MDEP; therefore, PM5 will not be applied. Taken together, this evidence supports the classification of c.365A>G as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP VCEP (specification version 1.0): PP1_moderate. PP3, PM1_supporting, PM2_supporting, PS3_supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA124457/MONDO:0015967/017

• Frequency: Genomes: not found (cov: 33)
• Consequence: HNF1A ENST00000257555.11 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:4
• Conservation: PhyloP100: 8.87

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 Likely_pathogenic. Variant got 6 ACMG points.

• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PM1: 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HNF1A	NM_000545.8	c.365A>G	p.Tyr122Cys	missense_variant	2/10	ENST00000257555.11	NP_000536.6
HNF1A	NM_001306179.2	c.365A>G	p.Tyr122Cys	missense_variant	2/10		NP_001293108.2
HNF1A	NM_001406915.1	c.365A>G	p.Tyr122Cys	missense_variant	2/9		NP_001393844.1
HNF1A	XM_024449168.2	c.365A>G	p.Tyr122Cys	missense_variant	2/9		XP_024304936.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HNF1A	ENST00000257555.11	c.365A>G	p.Tyr122Cys	missense_variant	2/10	1	NM_000545.8	ENSP00000257555	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4

Revision: reviewed by expert panel

Submissions by phenotype

Monogenic diabetes Pathogenic:1

Likely pathogenic, reviewed by expert panel

curation

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Aug 19, 2021

The c.395A>G variant in the HNF1 homeobox A gene, HNF1A, causes an amino acid change of tyrosine to cysteine at codon 122 (p.(Y122C)) of NM_000545.8. This variant is located within the DNA binding domain (codons 107-174) of HNF1A, which is defined as critical for the protein’s function by the ClinGen MDEP (PM1_Supporting). This variant is also predicted to be deleterious by computational evidence, with a REVEL score of 0.977, which is greater than the MDEP threshold of 0.70 (PP3). This variant is absent from gnomAD v2.1.1 (PM2_Supporting) and was identified in two individuals with diabetes; however, the MODY probability is unable to be calculated due to lack of clinical information (PMID:9097962, internal lab contributor). The variant also segregated with diabetes with four informative meioses in one family with MODY (PP1_Moderate; PMID:9097962). Additionally, functional studies demonstrated the p.Tyr122Cys protein has DNA binding and transactivation below 40% of wild type, indicating that this variant impacts protein function (PMID:10585442). Another missense variant, c.364T>C (p.Tyr122His) has been classified as a VUS by the ClinGen MDEP; therefore, PM5 will not be applied. Taken together, this evidence supports the classification of c.365A>G as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP VCEP (specification version 1.0): PP1_moderate. PP3, PM1_supporting, PM2_supporting, PS3_supporting. -

Maturity onset diabetes mellitus in young Pathogenic:1

Likely pathogenic, criteria provided, single submitter

research

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

-

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 rs137853237 with MODY3. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 25, 2022

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 14930). This missense change has been observed in individual(s) with maturity-onset diabetes of the young (PMID: 9097962). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 122 of the HNF1A protein (p.Tyr122Cys). -

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

Pathogenic, no assertion criteria provided

literature only

OMIM

Apr 01, 1997

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	.;D;D;D;D;.
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	0.98	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	A;A;A;A;A
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-8.0	D;.;.;.;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;.;.;.;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;D
Polyphen		1.0	.;.;.;.;.;D
Vest4		0.99
MutPred		0.89		Gain of catalytic residue at L123 (P = 0.0107);Gain of catalytic residue at L123 (P = 0.0107);Gain of catalytic residue at L123 (P = 0.0107);Gain of catalytic residue at L123 (P = 0.0107);Gain of catalytic residue at L123 (P = 0.0107);Gain of catalytic residue at L123 (P = 0.0107);
MVP		0.99
MPC		2.4
ClinPred		1.0	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
gMVP		0.98

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: rs137853237; hg19: chr12-121426674; COSMIC: COSV57460488;