1-40078640-T-G

Variant names:

• chr1-40078640-T-G
• rs766163400
• NM_000310.4:c.646A>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000310.4(PPT1):​c.646A>C​(p.Lys216Gln) variant causes a missense change. The variant allele was found at a frequency of 0.00000657 in 152,186 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. K216R) has been classified as Uncertain significance.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: PPT1 NM_000310.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.88
• Publications: 4 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: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen, G2P, Orphanet, Myriad Women’s Health

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000310.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.869

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PPT1	NM_000310.4	MANE Select	c.646A>C	p.Lys216Gln	missense	Exon 7 of 9	NP_000301.1
	PPT1	NM_001363695.2		c.646A>C	p.Lys216Gln	missense	Exon 7 of 8	NP_001350624.1
	PPT1	NM_001142604.2		c.337A>C	p.Lys113Gln	missense	Exon 4 of 6	NP_001136076.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PPT1	ENST00000642050.2	MANE Select	c.646A>C	p.Lys216Gln	missense	Exon 7 of 9	ENSP00000493153.1
	PPT1	ENST00000433473.8	TSL:1	c.643A>C	p.Lys215Gln	missense	Exon 7 of 9	ENSP00000394863.4
	PPT1	ENST00000530704.6	TSL:1	n.*269A>C		non_coding_transcript_exon	Exon 7 of 9	ENSP00000431655.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152186 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152186 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74358

African (AFR) AF: 0.00 AC: 0 AN: 41448

American (AMR) AF: 0.00 AC: 0 AN: 15278

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jan 06, 2025

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.20
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Uncertain	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.98	D
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.87	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H
PhyloP100		3.9
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-2.6	D
REVEL	Pathogenic	0.82
Sift	Benign	0.059	T
Sift4G	Uncertain	0.057	T
Polyphen		0.96	D
Vest4		0.59
MVP		0.99
MPC		0.42
ClinPred		0.98	D
GERP RS		4.0
Varity_R		0.80
gMVP		0.70
Mutation Taster		=64/36	polymorphism

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

Other links and lift over

dbSNP: rs766163400; hg19: chr1-40544312;