NM_000545.8:c.977C>T
Variant summary
Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS2
The NM_000545.8(HNF1A):c.977C>T(p.Ala326Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000805 in 1,614,004 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. A326A) has been classified as Likely benign.
Frequency
Consequence
NM_000545.8 missense
Scores
Clinical Significance
Conservation
Publications
- monogenic diabetesInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- type 1 diabetes mellitus 20Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Laboratory for Molecular Medicine, Genomics England PanelApp
- diabetes mellitus, noninsulin-dependentInheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
- maturity-onset diabetes of the young type 3Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
- hyperinsulinism due to HNF1A deficiencyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- maturity-onset diabetes of the youngInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- nonpapillary renal cell carcinomaInheritance: Unknown Classification: NO_KNOWN Submitted by: Labcorp Genetics (formerly Invitae)
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ACMG classification
Our verdict: Benign. The variant received -7 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| HNF1A | NM_000545.8 | c.977C>T | p.Ala326Val | missense_variant | Exon 5 of 10 | ENST00000257555.11 | NP_000536.6 | |
| HNF1A | NM_001306179.2 | c.977C>T | p.Ala326Val | missense_variant | Exon 5 of 10 | NP_001293108.2 | ||
| HNF1A | NM_001406915.1 | c.977C>T | p.Ala326Val | missense_variant | Exon 5 of 9 | NP_001393844.1 | ||
| HNF1A | XM_024449168.2 | c.977C>T | p.Ala326Val | missense_variant | Exon 5 of 9 | XP_024304936.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| HNF1A | ENST00000257555.11 | c.977C>T | p.Ala326Val | missense_variant | Exon 5 of 10 | 1 | NM_000545.8 | ENSP00000257555.5 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152154Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000477 AC: 12AN: 251390 AF XY: 0.0000368 show subpopulations
GnomAD4 exome AF: 0.00000821 AC: 12AN: 1461850Hom.: 0 Cov.: 35 AF XY: 0.00000688 AC XY: 5AN XY: 727228 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152154Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74340 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not specified Uncertain:1Benign:1
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Variant summary: HNF1A c.977C>T (p.Ala326Val) results in a non-conservative amino acid change in 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 4.8e-05 in 251390 control chromosomes. The observed variant frequency is approximately 2 fold of the estimated maximal expected allele frequency for a pathogenic variant in HNF1A causing Maturity Onset Diabetes Of The Young 3 phenotype (2.5e-05). c.977C>T has been reported in the literature in individuals affected with Type 2 Diabetes (Althari_2020, Bonnefond_2020, Stalbow_2023). These report(s) do not provide unequivocal conclusions about association of the variant with Maturity Onset Diabetes Of The Young 3. One publication reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect (Althari_2020). The following publications have been ascertained in the context of this evaluation (PMID: 32910913, 33046911, 36216889). ClinVar contains an entry for this variant (Variation ID: 435425). Based on the evidence outlined above, the variant was classified as likely benign. -
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
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Maturity onset diabetes mellitus in young Uncertain:1
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. However, more evidence is required to confer the association of this particular variant rs369764257 with MODY3. -
Maturity-onset diabetes of the young type 3 Benign:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at