rs386833665

Positions:

• chr1-40076901-A-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000310.4(PPT1):​c.739T>C​(p.Tyr247His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000752 in 1,461,820 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y247C) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: PPT1 NM_000310.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 7.35

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain 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 chr1-40076900-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 379909.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.982
• PP5: Variant 1-40076901-A-G is Pathogenic according to our data. Variant chr1-40076901-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 56214.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-40076901-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PPT1	NM_000310.4	c.739T>C	p.Tyr247His	missense_variant	8/9	ENST00000642050.2	NP_000301.1
PPT1	NM_001142604.2	c.430T>C	p.Tyr144His	missense_variant	5/6		NP_001136076.1
PPT1	NM_001363695.2	c.726+1659T>C		intron_variant			NP_001350624.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PPT1	ENST00000642050.2	c.739T>C	p.Tyr247His	missense_variant	8/9		NM_000310.4	ENSP00000493153.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251396 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135872

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: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000752 AC: 11 AN: 1461820 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 727212

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: 0.00000899

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neuronal ceroid lipofuscinosis 1 Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 12, 2024	- -
Likely pathogenic, no assertion criteria provided	literature only	Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 08, 2023	For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Tyr247 amino acid residue in PPT1. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects PPT1 function (PMID: 11440996, 29631617). 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. ClinVar contains an entry for this variant (Variation ID: 56214). This missense change has been observed in individual(s) with neuronal ceroid lipofuscinosis (PMID: 9664077, 23857568). This variant is present in population databases (rs386833665, gnomAD 0.002%). This sequence change replaces tyrosine, which is neutral and polar, with histidine, which is basic and polar, at codon 247 of the PPT1 protein (p.Tyr247His). -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Dec 22, 2016

- -

Neuronal ceroid lipofuscinosis Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jun 06, 2023

Variant summary: PPT1 c.739T>C (p.Tyr247His) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251396 control chromosomes (gnomAD). c.739T>C has been reported in the literature in individuals affected with Neuronal Ceroid-Lipofuscinosis (Batten Disease) (examples: Das_1998 and Miller_2013). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in <10% of normal activity (example: Das_2001). A different variant affecting the same residue c.740A>G (p.Tyr247Cys) is classified likely pathogenic in ClinVar (ID 379909), suggesting this residue may be critical for the normal protein function. The following publications have been ascertained in the context of this evaluation (PMID: 11440996, 9664077, 23857568, 29631617, 11073228). Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.53
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;.;.;.;.;.;.
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	.;D;D;D;D;D;D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	H;.;.;.;.;.;.
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-4.8	.;.;D;.;.;D;.
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	.;.;D;.;.;D;.
Sift4G	Pathogenic	0.0	.;.;D;.;.;D;.
Polyphen		1.0	D;.;.;.;.;D;.
Vest4		0.82, 0.74
MutPred		0.91		Gain of disorder (P = 0.0296);.;.;.;Gain of disorder (P = 0.0296);.;.;
MVP		1.0
MPC		0.66
ClinPred		0.99	D
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.95
gMVP		0.69

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: rs386833665; hg19: chr1-40542573;