chr15-24975420-A-C

Position:

• chr15-24975420-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_003097.6(SNRPN):​c.66A>C​(p.Gln22His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: SNRPN NM_003097.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.590

Genes affected

SNRPN (HGNC:11164): (small nuclear ribonucleoprotein polypeptide N) This gene is located within the Prader-Willi Syndrome critical region on chromosome 15 and is imprinted and expressed from the paternal allele. It encodes a component of the small nuclear ribonucleoprotein complex, which functions in pre-mRNA processing and may contribute to tissue-specific alternative splicing. Alternative promoter use and alternative splicing result in a multitude of transcript variants encoding the same protein. Transcript variants that initiate at the CpG island-associated imprinting center may be bicistronic and also encode the SNRPN upstream reading frame protein (SNURF) from an upstream open reading frame. In addition, long spliced transcripts for small nucleolar RNA host gene 14 (SNHG14) may originate from the promoters at this locus and share exons with this gene. Alterations in this region are associated with parental imprint switch failure, which may cause Angelman syndrome or Prader-Willi syndrome. [provided by RefSeq, Mar 2017]

SNHG14 (HGNC:):

SNURF (HGNC:11171): (SNRPN upstream open reading frame) This gene is located within the Prader-Willi Syndrome critical region on chromosome 15. Transcripts produced from this gene initiate at an imprinting center and are paternally-imprinted. These transcripts may be bicistronic and also encode SNRPN (small nuclear ribonucleoprotein polypeptide N) from a downstream open reading frame. The small protein represented by this gene is encoded by an evolutionarily-conserved upstream open reading frame and is localized to the nucleus. Extensive alternative splicing and promoter usage occurs in this region and the full-length nature of some of these transcripts has not been determined. Alterations in the imprinting center are associated with parental imprint switch failure, which may cause Angelman syndrome or Prader-Willi syndrome. [provided by RefSeq, Mar 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SNRPN	NM_003097.6	c.66A>C	p.Gln22His	missense_variant	5/10	ENST00000390687.9	NP_003088.1
SNHG14	NR_146177.1	n.968A>C		non_coding_transcript_exon_variant	8/148

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SNRPN	ENST00000390687.9	c.66A>C	p.Gln22His	missense_variant	5/10	1	NM_003097.6	ENSP00000375105	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 09, 2022

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Uncertain	0.029	T
BayesDel_noAF	Benign	-0.20
CADD	Benign	20
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.66	D;D;D;D;D;.;D;.;D;D
Eigen	Benign	-0.29
Eigen_PC	Benign	-0.57
FATHMM_MKL	Benign	0.70	D
LIST_S2	Uncertain	0.97	.;.;.;.;.;D;.;D;D;D
M_CAP	Benign	0.015	T
MetaRNN	Uncertain	0.54	D;D;D;D;D;D;D;D;D;D
MetaSVM	Benign	-0.67	T
MutationAssessor	Pathogenic	3.1	M;M;M;M;M;.;M;.;.;M
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-4.3	D;.;.;D;D;.;.;D;.;.
REVEL	Uncertain	0.36
Sift	Uncertain	0.027	D;.;.;D;D;.;.;D;.;.
Sift4G	Uncertain	0.024	D;.;.;D;D;D;D;D;D;D
Polyphen		1.0	D;D;D;D;D;.;D;.;.;D
Vest4		0.71
MutPred		0.44		.;.;.;.;.;.;.;Gain of sheet (P = 0.0827);.;.;
MVP		0.77
MPC		1.7
ClinPred		1.0	D
GERP RS		-4.5
Varity_R		0.20
gMVP		0.44

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr15-25220567;