NM_000391.4:c.622C>G

Variant names:

• chr11-6617040-G-C
• rs119455955
• NM_000391.4:c.622C>G

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_000391.4(TPP1):​c.622C>G​(p.Arg208Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,860 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R208Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TPP1 NM_000391.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.17
• Publications: 0 publications found

Genes affected

TPP1 (HGNC:2073): (tripeptidyl peptidase 1) This gene encodes a member of the sedolisin family of serine proteases. The protease functions in the lysosome to cleave N-terminal tripeptides from substrates, and has weaker endopeptidase activity. It is synthesized as a catalytically-inactive enzyme which is activated and auto-proteolyzed upon acidification. Mutations in this gene result in late-infantile neuronal ceroid lipofuscinosis, which is associated with the failure to degrade specific neuropeptides and a subunit of ATP synthase in the lysosome. [provided by RefSeq, Jul 2008]

TPP1 Gene-Disease associations (from GenCC):

• neuronal ceroid lipofuscinosis

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• neuronal ceroid lipofuscinosis 2

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P, Myriad Women’s Health, Genomics England PanelApp, PanelApp Australia
• autosomal recessive spinocerebellar ataxia 7

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, PanelApp Australia

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000391.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.809

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000391.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TPP1	NM_000391.4	MANE Select	c.622C>G	p.Arg208Gly	missense	Exon 6 of 13	NP_000382.3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TPP1	ENST00000299427.12	TSL:1 MANE Select	c.622C>G	p.Arg208Gly	missense	Exon 6 of 13	ENSP00000299427.6	O14773-1
	TPP1	ENST00000533371.6	TSL:1	c.-108C>G		5_prime_UTR	Exon 5 of 12	ENSP00000437066.1	O14773-2
	TPP1	ENST00000895469.1		c.622C>G	p.Arg208Gly	missense	Exon 6 of 13	ENSP00000565528.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461860 Hom.: 0 Cov.: 42 AF XY: 0.00000138 AC XY: 1 AN XY: 727236

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112000

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.86
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.75	D
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.46	D
MetaRNN	Pathogenic	0.81	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	M
PhyloP100		3.2
PrimateAI	Uncertain	0.57	T
PROVEAN	Uncertain	-3.8	D
REVEL	Pathogenic	0.83
Sift	Benign	0.043	D
Sift4G	Benign	0.38	T
Polyphen		1.0	D
Vest4		0.91
MutPred		0.55		Loss of MoRF binding (P = 0.0598)
MVP		0.99
MPC		0.85
ClinPred		0.99	D
GERP RS		4.1
Varity_R		0.77
gMVP		0.85
Mutation Taster		=31/69	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs119455955; hg19: chr11-6638271;