6-116877441-G-T

Position:

• chr6-116877441-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_173560.4(RFX6):​c.166G>T​(p.Glu56Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000697 in 1,434,572 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 Likely pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: RFX6 NM_173560.4 stop_gained
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: -0.560

Genes affected

RFX6 (HGNC:21478): (regulatory factor X6) The nuclear protein encoded by this gene is a member of the regulatory factor X (RFX) family of transcription factors. Studies in mice suggest that this gene is specifically required for the differentiation of islet cells for the production of insulin, but not for the differentiation of pancreatic polypeptide-producing cells. It regulates the transcription factors involved in beta-cell maturation and function, thus, restricting the expression of the beta-cell differentiation and specification genes. Mutations in this gene are associated with Mitchell-Riley syndrome, which is characterized by neonatal diabetes with pancreatic hypoplasia, duodenal and jejunal atresia, and gall bladder agenesis.[provided by RefSeq, Sep 2010]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 6-116877441-G-T is Pathogenic according to our data. Variant chr6-116877441-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3068603.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RFX6	NM_173560.4	c.166G>T	p.Glu56Ter	stop_gained	1/19	ENST00000332958.3
RFX6	XM_011535589.2	c.166G>T	p.Glu56Ter	stop_gained	1/18

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RFX6	ENST00000332958.3	c.166G>T	p.Glu56Ter	stop_gained	1/19	1	NM_173560.4	P1
RFX6	ENST00000487683.5	n.230G>T		non_coding_transcript_exon_variant	1/14	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.97e-7 AC: 1 AN: 1434572 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 710630

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: 0.0000121

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:1

Revision: criteria provided, single submitter

Submissions by phenotype

Maturity onset diabetes mellitus in young Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Molecular Genetics, Royal Melbourne Hospital

Mar 03, 2022

This sequence change in RFX6 is a nonsense variant predicted to cause a premature stop codon, p.(Glu56*), in biologically-relevant-exon 1/19 leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism (PMID: 29026101, 31001871). This variant is absent from gnomAD v2.1 and v3.1. To our knowledge, this variant has not been reported in the literature in any individuals with RFX6-related disease. Based on the classification scheme RMH Modified ACMG Guidelines v1.5.1, this variant is classified as LIKELY PATHOGENIC. Following criteria are met: PVS1, PM2_Supporting. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Benign	0.047
Eigen_PC	Benign	-0.33
FATHMM_MKL	Benign	0.031	N
MutationTaster	Benign	1.0	A
Vest4		0.33
GERP RS		-0.47

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: rs1774484879; hg19: chr6-117198604;