20-44355806-T-C

Position:

• chr20-44355806-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PS4_Moderate PVS1_Strong PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The c.2T>C variant in the hepatic nuclear factor-alpha gene, HNF4A, results in the loss of the initiation codon (p.Met1?) of NM_175914.5. By altering the start codon of the coding sequence, this variant may cause a truncated or absent protein in a gene in which loss-of-function is an established disease mechanism (PVS1_Strong; PMID:23348805). This variant is only present in one copy in the Latino/Admixed American subpopulation in gnomAD v2.1.1 and therefore a Popmax FAF is unavailable. Still, the variant meets the ClinGen MDEP threshold for PM2_Supporting (gnomAD 2.1.1 Popmax FAF ≤ 1:333,000 (≤ 0.000003 or 0.0003%) in gnomAD European Non-Finnish population AND ≤ 2 copies observed in ENF AND ≤ 1 copy in any other founder or non-founder population) (PM2_Supporting). This variant was identified in four unrelated individuals with non-autoimmune or absolute/near-absolute insulin-deficient diabetes (PS4_Moderate; internal lab contributors). In summary, c.2T>C meets the criteria to be classified as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 2.0.0, approved 10/11/2023): PVS1_Strong, PS4_Moderate, PM2_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA409109840/MONDO:0015967/085

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: HNF4A NM_175914.5 start_lost
• Clinical Significance: Likely pathogenic reviewed by expert panel P:2 U:2 O:1
• Conservation: PhyloP100: 4.66

Genes affected

HNF4A (HGNC:5024): (hepatocyte nuclear factor 4 alpha) The protein encoded by this gene is a nuclear transcription factor which binds DNA as a homodimer. The encoded protein controls the expression of several genes, including hepatocyte nuclear factor 1 alpha, a transcription factor which regulates the expression of several hepatic genes. This gene may play a role in development of the liver, kidney, and intestines. Mutations in this gene have been associated with monogenic autosomal dominant non-insulin-dependent diabetes mellitus type I. Alternative splicing of this gene results in multiple transcript variants encoding several different isoforms. [provided by RefSeq, Apr 2012]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HNF4A	NM_175914.5	c.2T>C	p.Met1?	start_lost	1/10	ENST00000316673.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HNF4A	ENST00000316673.9	c.2T>C	p.Met1?	start_lost	1/10	1	NM_175914.5
HNF4A	ENST00000457232.5	c.2T>C	p.Met1?	start_lost	1/10	1
HNF4A	ENST00000609795.5	c.2T>C	p.Met1?	start_lost	1/8	1
HNF4A	ENST00000609262.5	c.-230T>C		5_prime_UTR_variant	1/4	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000404 AC: 1 AN: 247240 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 134596

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461380 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726960

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Uncertain:2 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:1 Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Oct 02, 2019	Has not been previously published as pathogenic or benign to our knowledge -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 27, 2023	This sequence change affects the initiator methionine of the HNF4A mRNA. The next in-frame methionine is located at codon 71. This variant is present in population databases (no rsID available, gnomAD 0.003%). Disruption of the initiator codon has been observed in individual(s) with maturity-onset diabetes of the young (PMID: 21683639, 30977832). ClinVar contains an entry for this variant (Variation ID: 689636). This variant disrupts a region of the HNF4A protein in which other variant(s) (p.Arg63Trp) have been determined to be pathogenic (PMID: 20164212, 25819479, 28458902, 31875549). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Monogenic diabetes Pathogenic:1

Likely pathogenic, reviewed by expert panel

curation

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Jan 02, 2024

The c.2T>C variant in the hepatic nuclear factor-alpha gene, HNF4A, results in the loss of the initiation codon (p.Met1?) of NM_175914.5. By altering the start codon of the coding sequence, this variant may cause a truncated or absent protein in a gene in which loss-of-function is an established disease mechanism (PVS1_Strong; PMID: 23348805). This variant is only present in one copy in the Latino/Admixed American subpopulation in gnomAD v2.1.1 and therefore a Popmax FAF is unavailable. Still, the variant meets the ClinGen MDEP threshold for PM2_Supporting (gnomAD 2.1.1 Popmax FAF <= 1:333,000 (<= 0.000003 or 0.0003%) in gnomAD European Non-Finnish population AND <= 2 copies observed in ENF AND <= 1 copy in any other founder or non-founder population) (PM2_Supporting). This variant was identified in four unrelated individuals with non-autoimmune or absolute/near-absolute insulin-deficient diabetes (PS4_Moderate; internal lab contributors). In summary, c.2T>C meets the criteria to be classified as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 2.0.0, approved 10/11/2023): PVS1_Strong, PS4_Moderate, PM2_Supporting. -

Fanconi renotubular syndrome 4 with maturity-onset diabetes of the young Uncertain:1

Uncertain significance, criteria provided, single submitter

research

HudsonAlpha Institute for Biotechnology, HudsonAlpha Institute for Biotechnology

Jul 01, 2019

ACMG codes: PVS1 -

Maturity onset diabetes mellitus in young Other:1

Uncertain risk allele, criteria provided, single submitter

research

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

-

Potent mutations in HNF4A are associated with poor insulin secretion in response to hyperglycemia. Associated with MODY1. Patients initially respond well to sulfonylureas but eventually become insulin dependent. However, more evidence is required to ascertain the role of this particular variant rs1229650809 in MODY, yet. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Uncertain	0.072	D
BayesDel_noAF	Uncertain	-0.050
CADD	Benign	23
DANN	Uncertain	0.98
Eigen	Uncertain	0.41
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Benign	0.76	D
LIST_S2	Uncertain	0.90	D;D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	0.83	D
MutationTaster	Benign	1.0	D;D
PROVEAN	Benign	0.48	N;.;N
REVEL	Uncertain	0.58
Sift	Pathogenic	0.0	D;.;D
Sift4G	Benign	0.074	T;D;T
Polyphen		0.81, 0.60	.;P;P
Vest4		0.95
MutPred		0.98		Gain of glycosylation at M1 (P = 0.0041);Gain of glycosylation at M1 (P = 0.0041);Gain of glycosylation at M1 (P = 0.0041);
MVP		0.83
ClinPred		0.88	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1229650809; hg19: chr20-42984446;