19-7542920-C-T

Variant names:

• chr19-7542920-C-T
• rs777484615
• NM_001166114.2:c.1522C>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_001166114.2(PNPLA6):​c.1522C>T​(p.Arg508Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,461,338 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R508G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: PNPLA6 NM_001166114.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.27
• Publications: 2 publications found

Genes affected

PNPLA6 (HGNC:16268): (patatin like phospholipase domain containing 6) This gene encodes a phospholipase that deacetylates intracellular phosphatidylcholine to produce glycerophosphocholine. It is thought to function in neurite outgrowth and process elongation during neuronal differentiation. The protein is anchored to the cytoplasmic face of the endoplasmic reticulum in both neurons and non-neuronal cells. Mutations in this gene result in autosomal recessive spastic paraplegia, and the protein is the target for neurodegeneration induced by organophosphorus compounds and chemical warfare agents. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2009]

PNPLA6 Gene-Disease associations (from GenCC):

• ataxia-hypogonadism-choroidal dystrophy syndrome

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet
• PNPLA6-related spastic paraplegia with or without ataxia

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• retinal dystrophy-ataxia-pituitary hormone abnormality-hypogonadism syndrome

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• hereditary spastic paraplegia 39

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• cerebellar ataxia-hypogonadism syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• Laurence-Moon syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• trichomegaly-retina pigmentary degeneration-dwarfism syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the PNPLA6 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 29 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Gene score misZ: 4.3547 (above the threshold of 3.09). Trascript score misZ: 3.5139 (above the threshold of 3.09). GenCC associations: The gene is linked to retinal dystrophy-ataxia-pituitary hormone abnormality-hypogonadism syndrome, cerebellar ataxia-hypogonadism syndrome, PNPLA6-related spastic paraplegia with or without ataxia, ataxia-hypogonadism-choroidal dystrophy syndrome, trichomegaly-retina pigmentary degeneration-dwarfism syndrome, hereditary spastic paraplegia 39, Laurence-Moon syndrome.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PNPLA6	NM_001166114.2	c.1522C>T	p.Arg508Trp	missense_variant	Exon 12 of 32	ENST00000600737.6	NP_001159586.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PNPLA6	ENST00000600737.6	c.1522C>T	p.Arg508Trp	missense_variant	Exon 12 of 32	1	NM_001166114.2	ENSP00000473211.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000160 AC: 4 AN: 250214 AF XY: 0.00000738

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000868

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1461338 Hom.: 0 Cov.: 35 AF XY: 0.00000275 AC XY: 2 AN XY: 726972

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000671 AC: 3 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53034

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111886

Other (OTH) AF: 0.00 AC: 0 AN: 60376

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 39 Uncertain:1

Jul 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is present in population databases (rs777484615, gnomAD 0.009%). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 469 of the PNPLA6 protein (p.Arg469Trp). This variant has not been reported in the literature in individuals affected with PNPLA6-related conditions. 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 409995). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Benign	-0.28	T
BayesDel_noAF	Benign	-0.45
CADD	Uncertain	25
DANN	Uncertain	1.0
Eigen	Benign	-0.016
Eigen_PC	Benign	0.028
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.98	.;D;D;D;D
M_CAP	Pathogenic	0.41	D
MetaRNN	Uncertain	0.62	D;D;D;D;D
MetaSVM	Benign	-0.95	T
PhyloP100		1.3
PrimateAI	Benign	0.43	T
PROVEAN	Uncertain	-3.5	D;D;D;D;.
REVEL	Benign	0.14
Sift	Uncertain	0.011	D;D;D;D;.
Sift4G	Uncertain	0.012	D;D;D;D;D
Polyphen		0.99	D;.;.;D;.
Vest4		0.53
MutPred		0.49		.;.;.;.;Gain of catalytic residue at L506 (P = 0.0028);
MVP		0.35
MPC		0.63
ClinPred		0.67	D
GERP RS		3.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.093
gMVP		0.53
Mutation Taster		=81/19	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: rs777484615; hg19: chr19-7607806; COSMIC: COSV55376965; COSMIC: COSV55376965;