15-24954621-T-A

Position:

• chr15-24954621-T-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001378251.1(SNRPN):​c.-548-7493T>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SNRPN NM_001378251.1 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.0330

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:37462): (small nucleolar RNA host gene 14) This gene is located within the Prader-Willi critical region and produces a long, spliced paternally-imprinted RNA that initiates within a common upstream promoter region shared by the SNRPN (small nuclear ribonucleoprotein polypeptide N) and SNURF genes. This transcript serves as a host RNA for the small nucleolar RNA, C/D box 115 and 116 clusters. This RNA extends in antisense into the region of the ubiquitin protein ligase E3A gene (UBE3A), and is thought to regulate imprinted expression of UBE3A in the brain. This transcript undergoes extensive alternative splicing, and may initiate and terminate at multiple locations within this genomic region. The full-length structure of all splice forms is not determined. [provided by RefSeq, Mar 2017]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.9).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SNRPN	NM_001378251.1	c.-548-7493T>A		intron_variant			NP_001365180.1
SNRPN	NM_001349454.2	c.-370-4117T>A		intron_variant			NP_001336383.1
SNRPN	NM_001349455.2	c.-390-7493T>A		intron_variant			NP_001336384.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SNRPN	ENST00000400097.5	c.-390-7493T>A		intron_variant		1		ENSP00000382969.1
SNRPN	ENST00000400100.5	c.-390-7493T>A		intron_variant		1		ENSP00000382972.1
SNRPN	ENST00000642807.1	c.-390-7493T>A		intron_variant				ENSP00000495345.1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.90
CADD	Benign	3.6
DANN	Benign	0.54

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: rs220030; hg19: chr15-25199768;