NM_000310.4:c.888G>A

Variant names:

• chr1-40074094-C-T
• rs386833670
• NM_000310.4:c.888G>A
• PPT1 p.Trp296*

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PVS1_Moderate PM2 PP5

The NM_000310.4(PPT1):​c.888G>A​(p.Trp296*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PPT1 NM_000310.4 stop_gained
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 7.69
• Publications: 3 publications found

Genes affected

PPT1 (HGNC:9325): (palmitoyl-protein thioesterase 1) The protein encoded by this gene is a small glycoprotein involved in the catabolism of lipid-modified proteins during lysosomal degradation. The encoded enzyme removes thioester-linked fatty acyl groups such as palmitate from cysteine residues. Defects in this gene are a cause of infantile neuronal ceroid lipofuscinosis 1 (CLN1, or INCL) and neuronal ceroid lipofuscinosis 4 (CLN4). Two transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Dec 2008]

PPT1 Gene-Disease associations (from GenCC):

• neuronal ceroid lipofuscinosis

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• neuronal ceroid lipofuscinosis 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp, G2P, ClinGen, Myriad Women's Health

ACMG classification

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

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0358 CDS is truncated, and there are 3 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-40074094-C-T is Pathogenic according to our data. Variant chr1-40074094-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 56219.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000310.4. 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
	PPT1	NM_000310.4	MANE Select	c.888G>A	p.Trp296*	stop_gained	Exon 9 of 9	NP_000301.1	P50897-1
	PPT1	NM_001363695.2		c.816G>A	p.Trp272*	stop_gained	Exon 8 of 8	NP_001350624.1	Q5T0S4
	PPT1	NM_001142604.2		c.579G>A	p.Trp193*	stop_gained	Exon 6 of 6	NP_001136076.1	P50897-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PPT1	ENST00000642050.2	MANE Select	c.888G>A	p.Trp296*	stop_gained	Exon 9 of 9	ENSP00000493153.1	P50897-1
	PPT1	ENST00000433473.8	TSL:1	c.885G>A	p.Trp295*	stop_gained	Exon 9 of 9	ENSP00000394863.4	A0A2C9F2P4
	PPT1	ENST00000530704.6	TSL:1	n.*511G>A		non_coding_transcript_exon	Exon 9 of 9	ENSP00000431655.1	E9PK48

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251384 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	-	-	Neuronal ceroid lipofuscinosis 1 (2)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	40
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	0.97	D
PhyloP100		7.7
Mutation Taster		=2/198	disease causing (ClinVar)

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs386833670;

hg19: chr1-40539766;