chr1-40080458-G-A

Position:

• chr1-40080458-G-A

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000310.4(PPT1):​c.566C>T​(p.Pro189Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000192 in 1,461,818 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P189R) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000019 (0 hom.)
• Consequence: PPT1 NM_000310.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.87

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a chain Palmitoyl-protein thioesterase 1 (size 278) in uniprot entity PPT1_HUMAN there are 37 pathogenic changes around while only 3 benign (93%) in NM_000310.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-40080458-G-C is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.985

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PPT1	NM_000310.4	c.566C>T	p.Pro189Leu	missense_variant	6/9	ENST00000642050.2	NP_000301.1
PPT1	NM_001363695.2	c.566C>T	p.Pro189Leu	missense_variant	6/8		NP_001350624.1
PPT1	NM_001142604.2	c.257C>T	p.Pro86Leu	missense_variant	3/6		NP_001136076.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PPT1	ENST00000642050.2	c.566C>T	p.Pro189Leu	missense_variant	6/9		NM_000310.4	ENSP00000493153	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251442 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135894

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000192 AC: 28 AN: 1461818 Hom.: 0 Cov.: 32 AF XY: 0.0000165 AC XY: 12 AN XY: 727216

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: 0.0000243

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neuronal ceroid lipofuscinosis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 08, 2022

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 189 of the PPT1 protein (p.Pro189Leu). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with PPT1-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PPT1 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.80
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;.;.;.;.;.;.
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;D;D;D;D;D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	M;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.63	T
PROVEAN	Pathogenic	-9.7	.;.;.;.;.;D;.
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0010	.;.;.;.;.;D;.
Sift4G	Uncertain	0.0030	.;.;.;.;.;D;.
Polyphen		1.0	D;.;.;.;.;P;.
Vest4		0.93
MutPred		0.88		Loss of ubiquitination at K191 (P = 0.0474);.;.;Loss of ubiquitination at K191 (P = 0.0474);Loss of ubiquitination at K191 (P = 0.0474);.;.;
MVP		0.98
MPC		0.52
ClinPred		1.0	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.72

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: rs386833658; hg19: chr1-40546130;