21-17796901-G-A

Position:

• chr21-17796901-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_001100420.2(C21orf91):​c.345C>T​(p.Asn115=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000558 in 1,613,408 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: 𝑓 0.000026 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: C21orf91 NM_001100420.2 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.770

Genes affected

C21orf91 (HGNC:16459): (chromosome 21 open reading frame 91) Predicted to be involved in cerebral cortex neuron differentiation and positive regulation of dendritic spine development. [provided by Alliance of Genome Resources, Apr 2022]

(HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.84).
• BP7: Synonymous conserved (PhyloP=0.77 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
C21orf91	NM_001100420.2	c.345C>T	p.Asn115=	synonymous_variant	3/5	ENST00000284881.9	NP_001093890.1
LOC124900465	XR_007067823.1	n.1605+40112G>A		intron_variant, non_coding_transcript_variant
C21orf91	NM_017447.4	c.345C>T	p.Asn115=	synonymous_variant	3/5		NP_059143.3
C21orf91	NM_001100421.2	c.345C>T	p.Asn115=	synonymous_variant	3/4		NP_001093891.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
C21orf91	ENST00000284881.9	c.345C>T	p.Asn115=	synonymous_variant	3/5	2	NM_001100420.2	ENSP00000284881	P4
	ENST00000428689.5	n.71+3343G>A		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152022 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461386 Hom.: 0 Cov.: 33 AF XY: 0.00000550 AC XY: 4 AN XY: 727044

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152022 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74266

Gnomad4 AFR AF: 0.0000483

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.84
CADD	Benign	4.2
DANN	Benign	0.53

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: rs2824495; hg19: chr21-19169218;