rs121908260

Positions:

• chr11-2160835-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PP3_Moderate PP5

The NM_000207.3(INS):​c.137G>A​(p.Arg46Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,352 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 35)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: INS NM_000207.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1 O:1
• Conservation: PhyloP100: 1.03

Genes affected

INS (HGNC:6081): (insulin) This gene encodes insulin, a peptide hormone that plays a vital role in the regulation of carbohydrate and lipid metabolism. After removal of the precursor signal peptide, proinsulin is post-translationally cleaved into three peptides: the B chain and A chain peptides, which are covalently linked via two disulfide bonds to form insulin, and C-peptide. Binding of insulin to the insulin receptor (INSR) stimulates glucose uptake. A multitude of mutant alleles with phenotypic effects have been identified, including insulin-dependent diabetes mellitus, permanent neonatal diabetes diabetes mellitus, maturity-onset diabetes of the young type 10 and hyperproinsulinemia. There is a read-through gene, INS-IGF2, which overlaps with this gene at the 5' region and with the IGF2 gene at the 3' region. [provided by RefSeq, May 2020]

INS-IGF2 (HGNC:33527): (INS-IGF2 readthrough) This locus includes two alternatively spliced read-through transcript variants which align to the INS gene in the 5' region and to the IGF2 gene in the 3' region. One transcript is predicted to encode a protein which shares the N-terminus with the INS protein but has a distinct and longer C-terminus, whereas the other transcript is a candidate for nonsense-mediated decay (NMD). The transcripts are imprinted and are paternally expressed in the limb and eye. [provided by RefSeq, Jul 2008]

INS-IGF2 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a peptide Insulin B chain (size 29) in uniprot entity INS_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) in NM_000207.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.905
• PP5: Variant 11-2160835-C-T is Pathogenic according to our data. Variant chr11-2160835-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 13391.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, not_provided=1, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
INS	NM_000207.3	c.137G>A	p.Arg46Gln	missense_variant	2/3	ENST00000381330.5	NP_000198.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
INS	ENST00000381330.5	c.137G>A	p.Arg46Gln	missense_variant	2/3	1	NM_000207.3	ENSP00000370731.5
INS-IGF2	ENST00000397270.1	c.137G>A	p.Arg46Gln	missense_variant	2/5	1		ENSP00000380440.1

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460352 Hom.: 0 Cov.: 88 AF XY: 0.00000275 AC XY: 2 AN XY: 726508

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 35

ClinVar

Significance: Conflicting classifications of pathogenicity

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

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Maturity-onset diabetes of the young type 10 Pathogenic:1 Other:1

Pathogenic, no assertion criteria provided	literature only	OMIM	Apr 01, 2008	- -
not provided, no classification provided	literature only	UniProtKB/Swiss-Prot	-	- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 28, 2023

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 46 of the INS protein (p.Arg46Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with autosomal dominant maturity-onset diabetes of the young type (PMID: 18192540, 20226046, 28478482). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 13391). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects INS function (PMID: 20948967, 25423173). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Diabetes mellitus, permanent neonatal 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

-

Potent mutations in the INS gene can cause early onset diabetes mellitus which is insulin dependent. May have poor response to sulfonylureas, mutations in this gene can cause beta cell destruction.Sufficient evidence is found to confer the association of this particular variant R46Q/ rs121908260 with permanent neonatal diabetes mellitus. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Benign	22
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.64	D;D;D;D;.;.
Eigen	Benign	0.091
Eigen_PC	Benign	-0.14
FATHMM_MKL	Benign	0.11	N
LIST_S2	Uncertain	0.95	D;.;.;D;D;D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D;D
MetaSVM	Pathogenic	0.79	D
MutationAssessor	Benign	0.69	N;.;.;.;.;.
PROVEAN	Uncertain	-3.3	D;D;D;D;D;D
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0010	D;D;D;D;D;D
Sift4G	Uncertain	0.0040	D;D;D;D;.;D
Polyphen		1.0	D;P;P;P;.;D
Vest4		0.74
MutPred		0.61		Loss of methylation at R46 (P = 0.0584);Loss of methylation at R46 (P = 0.0584);Loss of methylation at R46 (P = 0.0584);Loss of methylation at R46 (P = 0.0584);Loss of methylation at R46 (P = 0.0584);Loss of methylation at R46 (P = 0.0584);
MVP		0.82
MPC		0.81
ClinPred		0.99	D
GERP RS		1.9
Varity_R		0.87
gMVP		0.94

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: rs121908260; hg19: chr11-2182065; COSMIC: COSV99171120; COSMIC: COSV99171120;