Genetic Variant LPL:p.Ile221Thr (chr8-19954240-T-C) – ACMG Classification: Pathogenic (14 pts)

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PS3PM1PM5PP2PP3_StrongPP5

The NM_000237.3(LPL):c.662T>C(p.Ile221Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000223 in 1,614,058 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 Conflicting classifications of pathogenicity (no stars). ClinVar reports functional evidence for this variant: "SCV000472756: Functional studies demonstrated that despite finding the variant protein in the culture medium, the variant protein had virtually no lipolytic activity. Further, the amount of intracellular variant LPL protein was found to be higher than wildtype and it is suggested that the variant protein may not be secreted appropriately (Henderson et al. 1991)." and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I221N) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

LPL
NM_000237.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:12U:1

Conservation

PhyloP100: 7.63

Publications

15 publications found

Variant links:

Genes affected

LPL (HGNC:6677): (lipoprotein lipase) LPL encodes lipoprotein lipase, which is expressed in heart, muscle, and adipose tissue. LPL functions as a homodimer, and has the dual functions of triglyceride hydrolase and ligand/bridging factor for receptor-mediated lipoprotein uptake. Severe mutations that cause LPL deficiency result in type I hyperlipoproteinemia, while less extreme mutations in LPL are linked to many disorders of lipoprotein metabolism. [provided by RefSeq, Jul 2008]

LPL Gene-Disease associations (from GenCC):

familial lipoprotein lipase deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Laboratory for Molecular Medicine, Ambry Genetics
hyperlipidemia, familial combined, LPL related
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp

LPL links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 ACMG points.

PS3

PS3 evidence extracted from ClinVar submissions: SCV000472756: Functional studies demonstrated that despite finding the variant protein in the culture medium, the variant protein had virtually no lipolytic activity. Further, the amount of intracellular variant LPL protein was found to be higher than wildtype and it is suggested that the variant protein may not be secreted appropriately (Henderson et al. 1991).; SCV001590163: Experimental studies have shown that this missense change affects LPL function (PMID: 1702428).; SCV002069631: Functional study shows p.Ile221Thr disrupts the enzyme activity of LPL (PMID: 1674945).; SCV003918741: Published functional studies demonstrate that I221T results in defective LPL protein and inactive enzyme (Dichek et al., 1991; Henderson et al., 1991; Fojo et al., 1992; Peterson et al., 2002; Ooi et al., 2012; Wang et al., 2022); SCV006097232: PS3:Supporting; SCV003997136: "In vitro studies showed this alteration impacts protein function (Fojo SS et al. Eur J Epidemiol, 1992 May;8 Suppl 1:59-63; Peterson J et al. J Lipid Res, 2002 Mar;43:398-406)."

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000237.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chr8-19954240-T-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2583060.Status of the report is criteria_provided_single_submitter, 1 stars.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 52 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. Trascript score misZ: -0.36753 (below the threshold of 3.09). GenCC associations: The gene is linked to familial lipoprotein lipase deficiency, hyperlipidemia, familial combined, LPL related.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.939

PP5

Variant 8-19954240-T-C is Pathogenic according to our data. Variant chr8-19954240-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1529.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000237.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LPL	NM_000237.3	MANE Select	c.662T>C	p.Ile221Thr	missense	Exon 5 of 10	NP_000228.1	P06858

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
LPL	ENST00000650287.1	MANE Select	c.662T>C	p.Ile221Thr	missense	Exon 5 of 10	ENSP00000497642.1	P06858
LPL	ENST00000965928.1		c.662T>C	p.Ile221Thr	missense	Exon 7 of 12	ENSP00000635987.1
LPL	ENST00000965929.1		c.659T>C	p.Ile220Thr	missense	Exon 5 of 10	ENSP00000635988.1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152174

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251462

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000205

AC:

AN:

1461884

Hom.:

Cov.:

AF XY:

0.0000220

AC XY:

AN XY:

727242

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000504

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000243

AC:

AN:

1112004

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.502

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74346

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41438

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000465

Hom.:

Bravo

AF:

0.0000340

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (5)

Hyperlipoproteinemia, type I (4)

Cardiovascular phenotype (2)

Hyperlipidemia, familial combined, LPL related (2)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.90

BayesDel_addAF

Pathogenic

0.35

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.81

Eigen

Pathogenic

0.82

Eigen_PC

Pathogenic

0.80

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.94

M_CAP

Pathogenic

0.36

MetaRNN

Pathogenic

0.94

MetaSVM

Pathogenic

0.84

MutationAssessor

Uncertain

2.8

PhyloP100

7.6

PrimateAI

Pathogenic

0.83

PROVEAN

Pathogenic

-4.4

REVEL

Pathogenic

0.81

Sift

Uncertain

0.0010

Sift4G

Uncertain

0.0020

Polyphen

1.0

Vest4

0.96

MVP

0.99

MPC

0.49

ClinPred

0.96

GERP RS

6.2

Varity_R

0.93

gMVP

0.93

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over