chr1-40092407-G-C

Variant names:

• chr1-40092407-G-C
• rs1477732757
• NM_000310.4:c.225C>G

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_000310.4(PPT1):​c.225C>G​(p.Thr75Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000687 in 1,455,808 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. T75T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: PPT1 NM_000310.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.0140
• Publications: 0 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_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.84).
• BP7: Synonymous conserved (PhyloP=-0.014 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PPT1	NM_000310.4	c.225C>G	p.Thr75Thr	synonymous_variant	Exon 2 of 9	ENST00000642050.2	NP_000301.1
PPT1	NM_001363695.2	c.225C>G	p.Thr75Thr	synonymous_variant	Exon 2 of 8		NP_001350624.1
PPT1	NM_001142604.2	c.125-2895C>G		intron_variant	Intron 1 of 5		NP_001136076.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PPT1	ENST00000642050.2	c.225C>G	p.Thr75Thr	synonymous_variant	Exon 2 of 9		NM_000310.4	ENSP00000493153.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1455808 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 724696

African (AFR) AF: 0.00 AC: 0 AN: 33330

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26100

East Asian (EAS) AF: 0.00 AC: 0 AN: 39658

South Asian (SAS) AF: 0.00 AC: 0 AN: 86112

European-Finnish (FIN) AF: 0.0000187 AC: 1 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1106510

Other (OTH) AF: 0.00 AC: 0 AN: 60198

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.84
CADD	Benign	1.0
DANN	Benign	0.38
PhyloP100		-0.014
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=100/0	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: rs1477732757; hg19: chr1-40558079;