rs1555211448

Variant names:

• chr12-120989033-G-GT
• rs1555211448
• NM_000545.8:c.526+2dupT

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PP4_Moderate PM2_Supporting PP3

This summary comes from the ClinGen Evidence Repository: The c.526+2dup variant in the HNF1 homeobox A gene, HNF1A, is predicted to remove a canonical splice donor site in intron 2 of NM_000545.8. This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant was also identified in an individual with a clinical history highly specific for HNF1A-MODY (MODY probability calculator result >50%, negative genetic testing for HNF4A, and response to low dose sulfonylureas) (PP4_Moderate; internal lab contributors). The computational splicing predictor SpliceAI gives a score of 0.48 for donor loss, predicting that the variant disrupts the donor site of intron 2 of HNF1A (PP3). This variant was identified in three unrelated individuals with non-autoimmune and non-absolute/near-absolute insulin-deficient diabetes; however, PS4_Moderate cannot be applied because this number is below the ClinGen MDEP threshold (internal lab contributors). In summary, c.526+2dup 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): PM2_Supporting, PP4_Moderate, PP3. LINK:https://erepo.genome.network/evrepo/ui/classification/CA658658176/MONDO:0015967/017

• Frequency: Genomes: not found (cov: 33)
• Consequence: HNF1A NM_000545.8 splice_region, intron
• Clinical Significance: Uncertain significance reviewed by expert panel U:4
• Conservation: PhyloP100: 7.61
• Publications: 0 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 4 ACMG points.

• PM2: 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.526+2dupT		splice_region_variant, intron_variant	Intron 2 of 9	ENST00000257555.11	NP_000536.6
HNF1A	NM_001306179.2	c.526+2dupT		splice_region_variant, intron_variant	Intron 2 of 9		NP_001293108.2
HNF1A	NM_001406915.1	c.526+2dupT		splice_region_variant, intron_variant	Intron 2 of 8		NP_001393844.1
HNF1A	XM_024449168.2	c.526+2dupT		splice_region_variant, intron_variant	Intron 2 of 8		XP_024304936.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HNF1A	ENST00000257555.11	c.526+1_526+2insT		splice_donor_variant, intron_variant	Intron 2 of 9	1	NM_000545.8	ENSP00000257555.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: reviewed by expert panel

Submissions by phenotype

not specified Uncertain:1

Jul 05, 2017

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Monogenic diabetes Uncertain:1

Apr 15, 2022

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The c.526+2dup variant in the HNF1 homeobox A gene, HNF1A, is predicted to remove a canonical splice donor site in intron 2 of NM_000545.8. This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant was also identified in an individual with a clinical history highly specific for HNF1A-MODY (MODY probability calculator result greater than 50%, negative genetic testing for HNF4A, and response to low dose sulfonylureas) (PP4_Moderate; internal lab contributors). The computational splicing predictor SpliceAI gives a score of 0.48 for donor loss, predicting that the variant disrupts the donor site of intron 2 of HNF1A (PP3). This variant was identified in three unrelated individuals with non-autoimmune and non-absolute/near-absolute insulin-deficient diabetes; however, PS4_Moderate cannot be applied because this number is below the ClinGen MDEP threshold (internal lab contributors). In summary, c.526+2dup 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): PM2_Supporting, PP4_Moderate, PP3. -

Maturity onset diabetes mellitus in young Uncertain:1

-

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

Significance: Uncertain significance

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. However, more evidence is required to confer the association of this particular variant rs1555211448 with MODY3. -

not provided Uncertain:1

Sep 14, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 2 of the HNF1A gene. It does not directly change the encoded amino acid sequence of the HNF1A protein. It affects a nucleotide within the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with HNF1A-related conditions. ClinVar contains an entry for this variant (Variation ID: 447494). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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
PhyloP100		7.6

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.64		Position offset: -33
DS_DL_spliceai		0.99		Position offset: -1

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

Other links and lift over

dbSNP: rs1555211448; hg19: chr12-121426836;