15-64963674-G-A

Position:

• chr15-64963674-G-A

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 2P and 7B. PM2 BP4_Strong BP6_Moderate BP7

The NM_016630.7(SPG21):​c.873C>T​(p.Ala291=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,840 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: SPG21 NM_016630.7 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -3.17

Genes affected

SPG21 (HGNC:20373): (SPG21 abhydrolase domain containing, maspardin) The protein encoded by this gene binds to the hydrophobic C-terminal amino acids of CD4 which are involved in repression of T cell activation. The interaction with CD4 is mediated by the noncatalytic alpha/beta hydrolase fold domain of this protein. It is thus proposed that this gene product modulates the stimulatory activity of CD4. Mutations in this gene are associated with autosomal recessive spastic paraplegia 21 (SPG21), also known as mast syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2014]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.62).
• BP6: Variant 15-64963674-G-A is Benign according to our data. Variant chr15-64963674-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 705517.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=-3.17 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SPG21	NM_016630.7	c.873C>T	p.Ala291=	synonymous_variant	9/9	ENST00000204566.7
SPG21	NM_001127889.5	c.873C>T	p.Ala291=	synonymous_variant	9/9
SPG21	NM_001127890.5	c.792C>T	p.Ala264=	synonymous_variant	8/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SPG21	ENST00000204566.7	c.873C>T	p.Ala291=	synonymous_variant	9/9	1	NM_016630.7	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461840 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727228

Gnomad4 AFR exome AF: 0.0000597

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Aug 07, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.62
CADD	Benign	2.0
DANN	Benign	0.83
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs1595864905; hg19: chr15-65256015; COSMIC: COSV99200206; COSMIC: COSV99200206;